Also have Artificer: Enhanced Arcane Focus: A rod, staff, or wand gives a creature a +1 to spell attack rolls and ignores half-cover when making spell attacks. +2 at level 10.
Wand of the War Mage: Wand of the War Mage - Magic Items - D&D Beyond (dndbeyond.com) , while holding this wand, you gain a bonus to spell attack rolls determined by the wand’s rarity. In addition, you ignore half cover when making a spell attack. Uncommon rarity is +1, Rare is +2 and Very Rare is +3
Rod the Pact Keeper (for warlocks), while holding this rod, you gain a bonus to spell attack rolls and to the saving throw DCs of your warlock spells. The bonus is determined by the rod’s rarity. In addition, you can regain 1 warlock spell slot as an action while holding the rod. You can’t use this property again until you finish a long rest.
Weapon infusion (blacksmithing the orb/crystal into a weapon and the weapon counts as the focus) (this might be similiar to the materia system from final fantasy 7). This is possible with something like Ruby of the War Mage, described in Xanathar's Guide to Everything, states: Etched with eldritch runes, this 1-inch-diameter ruby allows you to use a simple or martial weapon as a spellcasting focus for your spells. For this property to work, you must attach the ruby to the weapon by pressing the ruby against it for at least 10 minutes. Thereafter, the ruby can't be removed unless you detach it as an action or the weapon is destroyed. Not even an Antimagic Field causes it to fall off. The ruby does fall off the weapon if your attunement to the ruby ends.
Here are some things I've been considering:
Selling, finding as loot or crafting a new focus: A classic upgrade grants a +1, +2, or +3 bonus to spell attack rolls and saving throws for spells cast through the focus. This can include PC modifying it themselves or paying a hireling to specialize it.
School Specialty: Grant advantage on concentration checks for a specific school of magic (e.g., Evocation) when cast through the focus.
Focus Sacrifice: For a powerful one-time effect, allow the caster to destroy the focus or expend a significant amount of its charges to unleash a powerful magical surge.
Metamagic Feats: Attach the ability to use specific Metamagic Feats (like Subtle Spell or Twinned Spell) a limited number of times per day through the focus.
Elemental Focus: Imbue the focus with an element (fire, ice, lightning etc.) allowing for bonus damage or riders on spells of that element.
Reduced Material Components: The focus can store a limited number of spell components, eliminating the need to carry a separate pouch.
Automatic Retrieval: Components vanish from the pouch and appear in the caster's hand when needed for a spell cast through the focus.
Component Substitution: The focus can substitute for specific, rare material components (at a cost).
Limited Charges: The focus can hold a number of charges that can be expended to activate special abilities like casting a specific spell at a higher level or creating a magical effect, or create a pool of charges that recharge on a long rest. These charges can be used to reduce the spell slot cost of a spell by one level.
Attunement Bonus: Upon attuning to a specific focus, the caster gains a passive bonus, like darkvision or resistance to a damage type.
Consumable Upgrades: The caster can find or craft consumable items that enhance the focus for a short duration (e.g., a vial of dragonfire for a fire damage boost).
Unique Focus Types:
Sentience: The focus becomes sentient, granting bonuses, advice, or even acting as a familiar.
Modular: The focus is built from interchangeable components, allowing players to customize its appearance and grant specific benefits based on the chosen parts.
Living: The focus is a captured or bonded creature that grants magical abilities based on its nature (e.g., a captured fire elemental for bonus to fire spells).
Symbiotic: The focus bonds with the caster, growing in power alongside them. It could unlock new abilities at milestones.
Cursed: A powerful focus with a drawback. Perhaps it drains health or whispers dark secrets.
Focus Rituals: The caster performs rituals to imbue the focus with temporary or permanent enhancements.
Elbow Room for Adjustments:
Focus Crafting System: Allow players to craft focuses with specific materials and enchantments, offering a high degree of customization.
Focus Sentience Tiers: Sentient focuses could have different levels of intelligence and abilities, evolving with the caster.
Focus Quests: Quests dedicated to unlocking the true potential of a focus, rewarding players with unique abilities.
Focus Growth vs. Spell Progression:
Focuses can enhance specific aspects of spellcasting (attack rolls, saves, etc.) while spells gain power through level and slot usage. This creates synergy and allows for strategic focus selection.
Additional Effects:
Spell Range: Increase the range of specific spells.
Spell Slot Recovery: Similar to the Rod of the Pact Keeper, the focus could allow for limited spell slot recovery on a short or long rest.
Bonus Proficiency: The focus could grant a bonus to a specific skill check related to magic, like Arcana or History.
Spellcasting Speed: Reduce the casting time of certain spells.
Area of Effect: Expand the area of effect for some spells.
Utility Abilities: Grant the focus non-combat utility functions like telepathy or object animation.
Ritual Casting Enhancement: The focus could reduce the casting time or material components for specific rituals.
Honor mention first to IamSposta's entry of using a magic item as a focus under Homebrew Items & Equipment FAQ #7: (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/131411-a-homebrewers-how-to-faq)
Also have Artificer: Enhanced Arcane Focus: A rod, staff, or wand gives a creature a +1 to spell attack rolls and ignores half-cover when making spell attacks. +2 at level 10.
Wand of the War Mage: Wand of the War Mage - Magic Items - D&D Beyond (dndbeyond.com) , while holding this wand, you gain a bonus to spell attack rolls determined by the wand’s rarity. In addition, you ignore half cover when making a spell attack. Uncommon rarity is +1, Rare is +2 and Very Rare is +3
Rod the Pact Keeper (for warlocks), while holding this rod, you gain a bonus to spell attack rolls and to the saving throw DCs of your warlock spells. The bonus is determined by the rod’s rarity. In addition, you can regain 1 warlock spell slot as an action while holding the rod. You can’t use this property again until you finish a long rest.
Weapon infusion (blacksmithing the orb/crystal into a weapon and the weapon counts as the focus) (this might be similiar to the materia system from final fantasy 7). This is possible with something like Ruby of the War Mage, described in Xanathar's Guide to Everything, states: Etched with eldritch runes, this 1-inch-diameter ruby allows you to use a simple or martial weapon as a spellcasting focus for your spells. For this property to work, you must attach the ruby to the weapon by pressing the ruby against it for at least 10 minutes. Thereafter, the ruby can't be removed unless you detach it as an action or the weapon is destroyed. Not even an Antimagic Field causes it to fall off. The ruby does fall off the weapon if your attunement to the ruby ends.
Here are some things I've been considering:
Unique Focus Types:
Elbow Room for Adjustments:
Focus Growth vs. Spell Progression:
Focuses can enhance specific aspects of spellcasting (attack rolls, saves, etc.) while spells gain power through level and slot usage. This creates synergy and allows for strategic focus selection.
Additional Effects:
Remember to Consider:
Evolution: The focus could change form or appearance as the caster grows in power, reflecting their magical journey.
Jeremy Crawford answered this on twitter:
And Mike Mearls answered this way:
Tools for easy reference
Rollable JOSN Generator for Rollable Tags (Credit to: MidniteOil21)