Proficiency Dice

Proficiency Dice: This optional rule replaces a character’s proficiency bonus with a proficiency die, adding more randomness to the game and making proficiency a less reliable indicator of mastery. Instead of adding a proficiency  bonus to an ability check, an attack roll, or saving throw, the character’s player rolls a die. The Proficiency Die table shows which die or dice to roll, as determined by the character’s level. Whenever a feature, such as the rogue’s Expertise, lets a character double his or her proficiency bonus, the player rolls the character’s proficiency die twice
instead of once. This option is intended for player characters and non player characters who have levels, as opposed to
monsters who don’t.

Level Proficiency Bonus Proficiency Die
1st-4th +2 1D4
5th-8th +3 1D6
9th-12th +4 1D8
13th-16th +5 1D10
17th-20th +6 1D12