House rules and changes to official conditions are marked with the ᴮᴹ tag.

BLINDED [CONDITION] ᴿᴬᵂ

While you have the Blinded condition, you experience the following effects.
Can't See. You can't see and automatically fail any ability check that requires sight.
Attacks Affected. Attack rolls against you have Advantage, and your attack rolls have Disadvantage.

ᴮᴹ The DM can impose Disadvantage on a saving throw against a visible effect when it makes narrative sense, such as a Dexterity saving throw against a Lightning Bolt zap.

BLOODIED [CONDITION] ᴮᴹ

A creature is Bloodied when its hit points are equal to or less than half its maximum hit points (rounded down).

While you have the Bloodied condition, you experience the following effects.
Wounded. You gain 1 Exhaustion level. This Exhaustion is temporary and immediately ends when you are no longer Bloodied.
Blood Rush. While you are in combat, you suppress the effects of the Exhaustion gained from this condition. In addition, you have a +1 bonus to melee attack rolls and Strength saving throws.
Adjudication. The DM can decide that certain creatures aren’t affected by the Bloodied condition or show no visible signs of damage. Other expressions may be used for flavor: Constructs and Undead are Battered, Oozes are Jellied, Plants are Wilted, and Elementals may be Fractured or Dispersed.

CHARMED [CONDITION] ᴿᴬᵂ

While you have the Charmed condition, you experience the following effects.
Can't Harm the Charmer. You can't attack the charmer or target the charmer with harmful abilities or magical effects.
Social Advantage. The charmer has Advantage on any ability check to interact socially with you.

Charm effects from specific monsters and spells may have additional benefits, as specified in the stats block or spell description. For example, a vampire might be able to force a Charmed target to attack an ally.

If another creature charms a Charmed creature with the same spell or effect, only the most powerful charm effect applies while the durations overlap (XGTE). This will be determined by comparing the spell slots used to cast the spells, or by the save DCs if spells were cast at the same level or if the charm effect doesn't have a spell level. If both "charms" are of equal strength, the most recent one takes effect while the durations overlap. 

CONCENTRATION

Some spells and other effects require Concentration to remain active, as specified in their descriptions. If the effect’s creator loses Concentration, the effect ends. If the effect has a maximum duration, the effect’s description specifies how long the creator can concentrate on it: up to 1 minute, 1 hour, or some other duration. The creator can end Concentration at any time (no action required). The following factors break Concentration.

Another Concentration Effect. You lose Concentration on an effect the moment you start casting a spell that requires Concentration or activate another effect that requires Concentration, unless the spell or effect has the (homebrew) Dual Concentration feature specified in its description.
Damage. If you take damage, you must succeed on a Constitution saving throw to maintain Concentration. The DC equals 10 or half the damage taken (round down), whichever number is higher, up to a maximum DC of 30.
ᴮᴹ Dazed. If you are Dazed by a spell or effect but take no damage, you must succeed on a DC 5 Constitution save to maintain Concentration. A natural 1 on this save is an automatic failure.  
ᴮᴹ Environmental Disturbance. The DM can decide that some environmental phenomena, such as a violent earthquake or a wave crashing over you while you’re on a storm-tossed ship, requires you to succeed on a DC 10 Constitution saving throw to maintain Concentration, even if you take no damage. 
Incapacitated or Dead. Your Concentration ends if you have the Incapacitated condition or you die.

DAZED [CONDITION] ᴮᴹ

While Dazed, you experience the following effects.
Limited Activity. You can only do one of the following things on your turn: move, use an action, or use a Bonus Action. 
Ending the Condition. The Lesser Restoration and Greater Restoration spells remove the Dazed condition. 
Immunity. A creature immune to the Stunned or Paralyzed condition is also immune to the Dazed condition.

When a Dazed creature is affected by a spell or effect that gives them an extra action on their turn (like the Haste spell or the fighter’s Action Surge feature), they can still take this extra action, in addition to the movement, action, or Bonus Action allowed by the Dazed condition. See also Concentration -> Dazed.

DEAFENED [CONDITION] ᴮᴹ

While you have the Deafened condition, you experience the following effects.
Can't Hear. You have Disadvantage on Wisdom (Perception) checks and automatically fail any ability check that specifically requires hearing. 
ᴮᴹ Concussive Dampening. You have Resistance to Thunder damage from natural concussive forces, such as storms and explosive shockwaves, and spells of 2nd level or lower that deal Thunder damage.
ᴮᴹ Spellcasting Affected. When you cast a spell with a Verbal component, roll a d20. On a 1–4, the spell fails due to misuttered words. The DM can also have the spellcaster roll on the Wild Magic Surge table if the spellcaster rolls a 1 on the d20. If the spell was cast using a spell slot, that slot is not expended. If you are both Deafened and muted (such as within magical silence), any spell with a Verbal component automatically fails. 

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Critical Failure. When you roll a natural 1 on a saving throw against an effect that deals Thunder damage, you are concussed by the blast. You gain the Dazed and Deafened conditions until the end of your next turn. If the DM rules the effect especially powerful (such as an explosion or a dragon’s thunderous roar), these conditions last for 1d4 turns instead. You can make a DC 13 Constitution saving throw at the end of each of your turns, ending both conditions on a success.

Thunder damage is mainly concussive, like a shockwave, but being Deafened should still provide protection. As for spells with Verbal components, the chanting of mystic words require a particular combination of sounds, with specific pitch and resonance (2014 PHB). Being Deafened should make it harder to pronounce these sounds. 

EXHAUSTION [CONDITION] 

While you are subjected to the Exhaustion Condition, you experience the following effects.
Levels of Exhaustion. This Condition is cumulative. Each time you receive it, you gain 1 Exhaustion level. You die if your Exhaustion level exceeds 5.
d20 Rolls Affected. When you make a d20 Test, you subtract twice your Exhaustion level from the d20 roll. 
Speed Affected. Each Exhaustion level reduces your Speed by 5.
ᴮᴹ Spell DC Affected. You suffer a -2 penalty to your spell save DC (no matter the Exhaustion level).
Ending the Condition. Finishing a Long Rest in a Safe Haven removes 1 Exhaustion level. Some spells, class features, and items also remove Exhaustion levels. When your Exhaustion level reaches 0, the condition ends.

Easy Variant. At the DM's option, tier 1 characters (level 1-4) and creatures of Challenge Rating 1 or lower may substract 1 x Exhaustion level from their d20 Tests rather than twice their Exhaustion level.

FRIGHTENED [CONDITION] ᴿᴬᵂ

While you have the Frightened condition, you experience the following effects.
Ability Checks and Attacks Affected. You have Disadvantage on ability checks and attack rolls while the source of fear is within line of sight. (DM adjudication.)
Can't Approach. You can't willingly move closer to the source of fear.

Critical Failure (DMG variant rule). If you fail the saving throw with a natural 1, the DM can subject you to another effect as long as the Frightened condition lasts (DM chooses or rolls 1d8):

• (1-3) You must take the Dash action on each of your turn and use your movement to get farther away from the source of your fear.
• (4-6) Attack rolls against you have Advantage.
• (7-8) You are also Dazed (i.e. you can do only one of the following on each of its turns: move, take an action, or take a Bonus Action). Reroll save at the end of each of your turns to end the Dazed condition. 

A monster is likely to flee if it starts its turn Bloodied and has the Frightened condition. In those circumstances, you can decide the monster flees (Dash or Disengage action to move away), or you can have it make a DC 10 Wisdom saving throw and flee or attempt to parley or surrender on a failed save. (DMG 2024)

GRAPPLING 

A creature can grapple another creature. Characters typically grapple by using an Unarmed Strike. Many monsters have special attacks that allow them to quickly grapple prey. However a grapple is initiated, it follows these rules. 

Unarmed Strike (Grapple). The target must succeed on a Strength or Dexterity saving throw (it chooses which), or it has the Grappled condition. The DC for the saving throw and any escape attempts equals 8 + Strength modifier + Proficiency Bonus. This grapple is possible only if the target is no more than one size larger than you and if you have a hand free to grab it. Successfully grappling a creature gives it the Grappled condition.

One Grapple per Hand. A creature must have a hand free to grapple another creature. Some stat blocks and game effects allow a creature to grapple using a tentacle, a maw, or another body part. Whatever part a grappler uses, it can grapple only one creature at a time with that part, and the grappler can’t use that part to target another creature unless it ends the grapple.

Note: a grapple -- like a shove -- counts as an attack, but not as an "attack roll" (d20 Test). Some game features specify if something is triggered by an attack or an attack roll. 

GRAPPLED [CONDITION] ᴿᴬᵂ

While you have the Grappled condition, you experience the following effects. 
Speed 0. Your Speed is 0 and can't increase.
Attacks Affected. You have Disadvantage on attack rolls against any target other than the grappler.
Movable. The grappler can drag or carry you when it moves, but every foot of movement costs 1 extra foot, unless you are Tiny or two or more Sizes smaller than the grappler.

Escaping a Grapple. A Grappled creature can use its action to make a Strength (Athletics) or Dexterity (Acrobatics) check against the grapple’s escape DC, ending the Condition on itself on a success. The Condition also ends if the grappler has the Incapacitated condition or if the distance between the Grappled target and the grappler exceeds the grapple's range. (Some spells and effects require a different check or saving throw to escape a grapple.)

ᴮᴹ If you have the Extra Attack feature, you can replace one of your attacks when you use your action to escape the grapple, instead of using your full action to do so, unless you are also Restrained. 

HIDE [ACTION] 

With the Hide action, you try to conceal yourself and make yourself silent.

Requirements. You must be Heavily Obscured, or behind Three-Quarters Cover or Total Cover, and out of any enemy’s line of sight. You can’t hide behind a creature only one size larger than you, unless you have a feature that allows it (such as the Halfling’s Naturally Stealthy trait). If you can see a creature, you can usually tell whether it can see you (DM’s discretion).
Finding a Hiding Spot. Unless you are in an empty room, you may suggest hiding places to the DM. The DM decides whether hiding is possible in the situation.
Stealth Check. Make a Dexterity (Stealth) check. Your result becomes the DC for creatures trying to detect you with the Search action (Perception check). The DM may instead use a creature’s Passive Perception.
Self-Awareness. If your Stealth result is below 15, you realize that your attempt is mediocre at best in the current circumstances.
Check Reroll. If the scene, environment, or situation changes, the DM may call for a new Dexterity (Stealth) check. You must use the new result.
Group Stealth. When the party moves stealthily together, the DM can have everyone roll Stealth and use the group’s average as the DC. For a grittier approach, the DM may instead use the lowest roll.

HIDDEN [CONDITION] ᴮᴹ 

Replaces the Invisible condition when hiding.

While Hidden, you are unheard as well as unseen. You experience the following effects:
Surprise. If you are Hidden when you roll Initiative, you have Advantage on the roll.
Concealed. You aren’t affected by any effect that requires its target to be seen unless the effect's creator can somehow see you. Any equipment you are wearing or carrying is also concealed.
ᴮᴹ Rogue Sneak. A Rogue, or a creature with Stealth expertise (double Proficiency), can sneak up to a target from behind or the side without ending the condition, provided the character stays in Dim Light or Darkness and beats the creature's Passive Perception. 
Attacks Affected. Attack Rolls against you have Disadvantage, and your Attack Rolls have Advantage. (Your first attack normally ends the Condition.)

The Condition ends on you immediately after any of the following occurrences: you make a sound louder than a whisper, an enemy finds you, you make an Attack Roll, you cast a Spell with a verbal component, or you are no longer Heavily Obscured or behind any Cover.

INCAPACITATED [CONDITION] 

While you have the Incapacitated condition, you experience the following effects.
Inactive. You can't take any action, Bonus Action, or Reaction.
No Concentration. Your Concentration is broken.
ᴮᴹ Speechless. You can't speak or use Telepathy, unless a rule states otherwise.
Surprised. If you're Incapacitated when you roll Initiative, you have Disadvantage on the roll.

INVISIBLE [CONDITION] 

While you have the Invisible condition, you experience the following effects:
Concealed. You aren’t affected by any effect that requires its target to be seen unless the effect's creator can somehow see you. If you become Invisible as part of a spell or other magical effect, any equipment you are wearing or carrying when you become invisible is also invisible.
ᴮᴹ Adaptive Illusion. Tiny objects that you pick up become invisible. Nonmagical substances that come in contact with you such as blood or flour become invisible, but can momentarily reveal your current location.
Attacks Affected. Attack rolls against you have Disadvantage, and your attack rolls have Advantage. If a creature can somehow see you, you don't gain this benefit against that creature.
ᴮᴹ Limited Stealth. A creature within 30 feet of you that doesn't have the Deafened condition knows your approximate location and can move to attack you. If you want to make sure you are unheard as well as unseen, you must take the Hide action (Stealth check), which can be countered by a creature with a successful Search action (Perception check).

A creature in melee combat with you can usually determine your approximate location; it might not see you, but you are making noise as you move around, breathing, shuffling, clipping bushes, hitting the cobblestone, stirring up dust, leaving footprints, stepping in a puddle, bumping into furniture, or swinging your weapon.  

The DM can decide that an invisible creature's location is unknown to combatants because of the environment, the combatants' attentiveness, or the distance separating the creature and the other combatants. They might be distracted or simply just not paying attention.

If a creature is Hidden as well as Invisible, the DM can impose Disadvantage on a creature's Wisdom (Perception) check to find its location when taking the Search action, especially if the Invisible creature is more than 30 feet away.

PARALYZED [CONDITION] ᴿᴬᵂ

While you have the Paralyzed condition, you experience the following effects.
Incapacitated. You have the Incapacitated condition, but can use Telepathy if you have this ability.
Speed 0. Your Speed is O and can't increase.
Saving Throws Affected. You automatically fail Strength and Dexterity saving throws.
Attacks Affected. Attack rolls against you have Advantage.
Automatic Critical Hits. Any attack roll that hits you is a Critical Hit if the attacker is within 5 feet of you.

PETRIFIED [CONDITION] ᴿᴬᵂ

While you have the Petrified condition, you experience the following effects.
Turned to Inanimate Substance. You are transformed, along with any nonmagical objects you are wearing and carrying, into a solid inanimate substance (usually stone). Your weight increases by a factor of ten and you cease aging.
Incapacitated. You have the Incapacitated condition, but can use Telepathy if you have this ability.
Speed 0. Your Speed is O and can't increase.
Attacks Affected. Attack rolls against you have Advantage.
Saving Throws Affected. You automatically fail Strength and Dexterity saving throws.
Resist Damage. You have Resistance to all damage.
Poison Immunity. You have Immunity to the Poisoned condition.

ᴮᴹ If you are Petrified for more than 7 days, you become Unconscious. When the Petrified condition ends, you gain 1 Exhaustion level and you are Blinded for 1 minute. You can make a DC 15 Constitution saving throw at the end of each of your turns. On a success, you are no longer Blinded.

POISONED [CONDITION] ᴿᴬᵂ

While you have the Poisoned condition, you experience the foIlowing effect.
Ability Checks and Attacks Affected. You have Disadvantage on attack rolls and ability checks.

ᴮᴹ Critical Failure. At the DM's option, if you roll a 1 on a saving throw that imposes the Poisoned condition, you also gain 1 Exhaustion level that lasts until the condition is removed.

PRONE [CONDITION]

While you have the Prone condition, you experience the following effects.
Restricted Movement. Your only movement options are to crawl or to spend an amount of movement equal to half your Speed (rounded down) to right yourself and thereby end the condition. If your Speed is 0, you can't right yourself. If you crawl, each foot of movement costs 1 extra foot (2 extra feet in Difficult Terrain).
Attacks Affected. You have Disadvantage on attack rolls. An attack roll against you has Advantage if the attacker is within 5 feet of you. Otherwise, that attack roll has Disadvantage, ᴮᴹ unless you are Huge or Gargantuan. 

RESTRAINED [CONDITION] ᴿᴬᵂ

While you have the Restrained condition, you experience the following effects.
Speed 0. Your Speed is O and can't increase.
Attacks Affected. Attack rolls against you have Advantage, and your attack rolls have Disadvantage.
Saving Throws Affected. You have Disadvantage on Dexterity saving throws.

STUNNED [CONDITION]

While you have the Stunned condition, you experience the following effects.
Incapacitated. You have the lncapacitated condition.
ᴮᴹ Stupefied. Your Speed is Halved and you can only speak falteringly (no spellcasting).
Saving Throws Affected. You automatically fail Strength and Dexterity saving throws.
Attacks Affected. Attack rolls against you have Advantage.
ᴮᴹ Adrenaline Recovery. If you fail three saving throws against the same instance of this condition, you have Advantage on further saving throws made to end it.

The 5.24 PHB nerfed the Stunned condition by removing the "you can't move and can speak only falteringly" effect. For verisimilitude, my version limits the creature's Speed but does not prevent movement entirely. 

SURPRISED [CONDITION]

If you are caught unaware by the start of combat, you are Surprised and experience the following effects.
Unprepared. When you roll Initiative, you have Disadvantage on the roll.
ᴮᴹ Flat-footed. You can't take a Reaction until the start of your turn.

The DM determines who might be surprised. If neither side tries to be stealthy, they usually notice each other. Otherwise, the DM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature on the opposing side (-5 Passive Perception score in Dim Light). A character or monster that doesn't notice a threat is surprised at the start of the encounter. A member of a group can be surprised even if the other members aren't. 

Surprised While Sleeping ᴮᴹ 
Characters who normally wear Medium or Heavy armor are assumed to remove that armor during a Long Rest unless the player states otherwise. Sleeping in Light armor has no adverse effect, but sleeping in Medium or Heavy armor makes full recovery difficult.

If you finish a Long Rest during which you slept in Medium or Heavy armor:

• You regain only half of your spent Hit Dice (rounded down).
• If you have any Exhaustion levels, the rest does not reduce them.
• You must succeed on a DC 10 Constitution saving throw or gain 1 level of Exhaustion.

UNCONSCIOUS [CONDITION]

While you have the Unconscious condition, you experience the following effects.
Inert. You have the Incapacitated and Prone conditions, and you drop whatever you're holding. When this condition ends, you remain Prone.
Speed 0. Your Speed is O and can't increase.
Attacks Affected. Attack rolls against you have Advantage.
Saving Throws Affected. You automatically fail Strength and Dexterity saving throws. Automatic Critical Hits. Any attack roll that hits you is a Critical Hit if the attacker is within 5 feet of you.
Unaware. You're unaware of your surroundings. ᴮᴹ If you are Unsconscious because you are sleeping, decrease your Passive Perception score by 10.

ᴮᴹ An Unconscious creature can't choose to fail a saving throw, or consent to anything.

Notes: Utility