I would like your opinion on this magic artifact I have created.

The Sword of Time

Weapon (longsword), artifact (requires attunement by a creature with a wisdom score of 18 or higher)

Attunement. The sword takes an entire 24 hours to attune to. When a creature attempts to attune to it with a wisdom score of 17 or lower, nothing will happen. If a creature that meets the requirements attempts to attune to the weapon, it will be surrounded in a sphere of blue light. The creature is frozen in time for the following 24 hours and is untouchable inside the sphere of light. To the creature, it will seem as if no time has passed at all between attunement and the end of the 24 hour period. Once attuned to, the sword cannot be unattuned unless the creature dies.

You gain a +3 bonus to attack and damage rolls made with this magic weapon. Additionally, this weapon deals a critical hit on a natural roll of 18-20.

• Foresight. You have a limited ability to see into the immediate future. While you hold the sword drawn, you can’t be surprised and have advantage on attack rolls, ability checks, and saving throws. Additionally, other creatures have disadvantage on attack rolls against.

• Frozen in Time. Your physical form cannot be changed from when you were attuned to the sword. Thus You stop aging. You are immune to any effect that would age you, and you can't die from old age. You are also immune to any spell or effect that would alter or change your shape. Even damage cannot last long on you. If you start your turn with at least 1 hit point, you regain 1d10 hit points.

• Attacks of Perception. When making an attack with this weapon, you use your choice of your Strength or Wisdom modifier for the attack and damage rolls. You must use the same modifier for both rolls.

• Accelerate Time. As a bonus action, you can put yourself under the haste spell without the need for concentration. You can do this as many times as your proficiency bonus.

• Spellcasting. The sword has 16 charges. You can use an action and expend 1 or more charges to cast one of the following spells (save DC 19) from it: Time Stop (6 charges), Slow “slow down time” (2 charges), Haste “speed up time” (2 charges), Hold Person “frozen in time”(1 charge), Blink “sends you forward 6 seconds” (2 charges), Gentle Repose “stops time” (1 charge), or Heal “rewinds damage” (5 charges). The sword regains 1d4 + 4 charges daily at dawn. The sword focuses on these spells if they require it. The sword can only focus on one spell at a time.

• Time Paralysis. When you deal a critical hit to a creature, it must make a DC 19 wisdom saving throw or be paralyzed and unaware of its surroundings for one round. The creature is frozen in time and to the creature, it seems as if it has just jumped forward in time by 6 seconds. If you so choose after dealing a critical hit, you can leave your weapon inside the creature you attacked. The creature will be indefinitely frozen in time until the weapon is removed.

• Sentience. The Sword of Time is a sentient, true neutral item with an Intelligence of 17, a Wisdom of 20, and a Charisma of 10. It has hearing and darkvision out to a range of 120 feet. It's only goal is to be used by someone for its purpose of combat. It wants you to use at least one of its spells every day.

I mean, It's an Artifact. You can't really make it "too powerful," as they are meant to be used as a plot device, and should be immensely powerful, even in the hands of someone relatively weak. I think you have accomplished this. I do, However, have a few comments.

• Add Artifact Properties (DMG page 219). They can be fun, and can help make Artifacts feel unique.

• There is a typo at the end of Foresight. It should read: Additionally, other creatures have disadvantage on attack rolls against you.
  • You could also simplify the ability by saying "While you hold the sword, you are under the effects of the Foresight spell."
• Accelerate time currently does not regain uses, and could be simplified. It should read:
  • Accelerate Time. As a bonus action, you can put yourself under the effects of the haste spell for one minute without the need for concentration. You can do this as many times as use this feature a number of times equal to your proficiency bonus, and you regain all expended uses of it when you finish a long rest.
• I like the spells you chose for Spellcasting. However, I would consider adding Time Ravage and Temporal Shunt to the list. Also, the line at the end is confusing. "The sword focuses on these spells if they require it." There is nothing in the game about "focusing" on spells. Assuming you mean concentration,  then there are no rules as to how concentration saves would work for an object. If it is concentration, then you don't need to specify that it can only concentrate on one spell at a time, as that is how concentration almost always works. If the idea of the ability is for the player to be able to have two concentration effects active, one from the sword and one from their own spellcasting, while only making concentration saves for the one that they cast, you could say the following: you can concentrate on two spells at a time, but only if one of the spells was cast from the sword. Furthermore, you do not make concentration saving throws for concentration spells cast from the sword. Clearly stating the ability is better adding flavor. For this reason, I would remove the quoted phrases after each spell. Mixing flavor in with the mechanics can get confusing, and players can add the flavor to the effects if they wish.

• lastly, you need to add languages and some way of communicating (probably telepathy) to the sentience trait.

This is super powerful. Even just giving the wielder foresight (without concentration) alone puts it above basically every other artifact, IMO. If it were me, I'd limit that ability to one minute each day. That being said, we can move forward. Here are my suggestions:

Frozen in Time. While you are attuned to the sword, you cease to age and you can't be aged magically. You are likewise immune to any spell or effect that would alter your form. Additionally, if you start your turn with at least 1 hit point, you regain 1d10 hit points.

Accelerate Time. As a bonus action, you can use the sword to cast the haste spell, targeting yourself, requiring no spell components or concentration. You can use this feature a number of times equal to your proficiency bonus, and regain all expended uses daily at dawn.

Spells. The sword has 16 charges. While holding the sword, you can use an action to expend 1 or more of its charges to cast one of the following spells from it (save DC 13): blink (3 charges), gentle repose (2 charges), haste (3 charges), heal (6 charges), or hold person (2 charges). The sword regains 1d4+4 expended charges daily at dawn. If a spell requires concentration, the sword can concentrate on it for you, but can concentrate on no more than one spell at a time.

Time Paralysis. When you score a critical hit with the sword, you can force the target to make a DC 19 Wisdom saving throw. On a failed save, the target is locked in a temporal stasis. For the duration, the target is petrified, along with anything they are carrying or wearing, and can’t be harmed or moved until the effect is ended. The effect lasts until the end of the target's next turn, or indefinitely if you choose to embed the sword in the target.

Also, you might consider a more flavorful name. I rather like something like "The Minute Hand" of "The Pendulum".

Quote from Heartofjuyomk2 >>

Even just giving the wielder foresight (without concentration) alone puts it above basically every other artifact, IMO. 

 

The eye of hand can one shot almost anything if they fail a DC 18 con save and gets unlimited castings of wish.

Quote from KthunkTheBarbarian >>

Quote from Heartofjuyomk2 >>

Even just giving the wielder foresight (without concentration) alone puts it above basically every other artifact, IMO. 

 

The eye of hand can one shot almost anything if they fail a DC 18 con save and gets unlimited castings of wish.

 
Yeah. *Basically* is carrying some weight, but not a lot.

I would work more on a good goal. "It wants to be used by you," is extremely convenient for the user and it doesn't do the weapon any favors in terms of characterization or importance. Artifacts aren't supposed to be that easy or subservient. They have desires that stretch beyond the scope of the adventurers, and the conflicts that can create provide a rich source of roleplay.

It also grounds the artifact in the world, giving players the sense that it was around long before the players came along, and will be around long after they're gone. That theirs is only one of many stories in the world. Most magic items are bit players in the PC's story - an artifact should feel the opposite way, the players being but a stepping-stone towards their final goal.

Quote from scatterbraind >>

I would work more on a good goal. "It wants to be used by you," is extremely convenient for the user and it doesn't do the weapon any favors in terms of characterization or importance. Artifacts aren't supposed to be that easy or subservient. They have desires that stretch beyond the scope of the adventurers, and the conflicts that can create provide a rich source of roleplay.

It also grounds the artifact in the world, giving players the sense that it was around long before the players came along, and will be around long after they're gone. That theirs is only one of many stories in the world. Most magic items are bit players in the PC's story - an artifact should feel the opposite way, the players being but a stepping-stone towards their final goal.

 
This is a good point. Perhaps a sword with time powers has a goal of preserving or destroying a specific timeline by killing or protecting key individuals. Or perhaps it wants to be present at moments of historical (or even future) significance.