Ok this maybe a dumb idea, but I think it would be really cool if there where none craftible items in minecraft that can be crafted with weapons, and armor to chance their function or enhance them in a way outside of their base uses.These ideas are in no order and are just well random.
found: rarely dropped by pillagers
function: when added to a crossbow (shapeless craft) changes its function from a slow single draw to a burst of arrows firing 3 arrows for every time you pull back the string.
Sword: [material] long blade
function: when added to a sword increases the range of attacks to one and a half blocks from the player. two blocks on diamond.
found: pillager camps.
function: when applied to shields gives them a thorns effect making any attacks damage the attacker.
found: any loot chest
function: can hold arrows as a nested inventory can only be oppened when in hands. Bows and crossbows will use arrows from quivers first. Quivers can hold 4 stacks in a one stack location.
quiver: potion chamber
found: pillagers rarely drop, pillagers that drop this fire poison arrows.
function: when crafted with a quiver adds a slot bellow the 4 arrow slots, any potion put in this slot will have its effect applied to all arrows shot. each potion lasts 24 shots.
[material] axe double head
found: rarely dropped by illagers
function: Ax does one more damage and destroys a 3x3x3 area of logs when used.
found: dungeon chests, villager trades
function: attached to chest armor, when attached armor may end up with bow/crossbow enchantments which apply to any bow/crossbow used.
Hoe: scythe head
found: farmer villager trades
function: replaces the head of a hoe, adding a 2 hearts worth of damage on a wooden one and causing it to affect a 3 wide area infront of the player good for making roads, cutting down hordes, and harvesting.
elytra: bat wings
found: dropped by bats.
function: hit space while gliding to flap wings each flap removes 2 from your hunger bar. same rules as sprinting apply.
hidden: bats will follow players with this equipped.
crossbow: strange contraption
function: the crossbow doesn't use arrows but instead XP, with each shot taking 10 XP instead of firing single shots fires a damaging beam like that of the guardians. think of it like minecrafts equivalent to a minigun, lots of attacks but low damage per attack.
note: can't fire if you have no EXP.