Multiclass Dip

Throughout the multiverse many adventures have honorably gone to the grave before their time. A certain novelist has collected a few of their relics, some still contain impressions of their former owners.

Barbarian: Barbarian's Garb a chest piece that gives 1 charge of Rage, Barbarian's Unarmored Defense, Danger Sense, & Reckless attack.

Bard: Bard's Lute gives Jack Of All Trades, 1 Bardic Inspiration, and Song of Rest.

War cleric: War Cleric's Amulet will give you the ability of a War Priest to make a bonus attack as well as a charge of channel divinity to use Guided strike, adds Heavy Armor Proficiency

Druid: Druid's Oak crook is a Quaterstaff that gives a few iconic Druid spells and a wildshape charge!

Fighter: Fighter's Undergarment will give any character a use of action surge & second wind

Paladin: Paladin Gloves is a pair of gauntlets that gives you Divine sense and Divine Smite, including a level 1 spell slot for anyone to use.

Ranger: Ranger's Gloves will give you both Two-weapon Fighting & archery fighting style.

Rogue: Rogue's Dagger will give you all 3 cunning action abilities as well as sneak attack!

Sorcerer: Sorcerer's Ring provides you with 2 sorcery points and the metamage Twinspell. Only useful if you've already got spell slots.

Warlock: Warlock's Pendant gives you 1 Warlock spell slot, the iconic Eldritch blast, and the only level 3 ability here, Pact of the Blade. Works best with a Charisma based character.

Not ready yet:

This is my very first mod, made with no prior experience, so there might be a few things to work out. Please let me know! For modding purposes these items use the item "Shield of Devotion" as a template. I have done what testing I know to do and found that using the resource granted by an item on one character and then sending the item to another character will let the other character use the resources as well. Shield of Devotion also does this, at least in my testing it did. Further, any item that grants 2 of one type resource, if you use only 1 charge and then unequip that item you will lose both charges until you long/short rest, depending on the item.