Wondrous Item, uncommon (requires attunement by a Requires attunement)
Description - A set of 7 polyhedral dice in a sparkling sapphire leather pouch.
Spirit of the item - Your D&D dice, which bounce around in your character’s pocket and determines their fate
Effect (no action)
Lucky number - Upon attunement, player picks their favorite number, 1-20. When player rolls that number on any d20 roll, it counts as a crit or natural 20, once per day.
1 Charge per in-game day - Recharges each day at sunrise
Notes: Requires attunement
You cannot choose a natural 1.
Credit goes to caseyplusc.