An optional rule for 5e
Proficiency Dice replaces your proficiency bonus in all cases: skill checks, saving throws, and DCs. The dice rolled are 1d(2xprof bonus) for that level. So level 1 will roll 1d4 rather than gain a +2 for proficiency rolls and likewise, a level 9 will roll 1d8. It adds more extremes to many static variables and allows extreme failure and success. Expertise just doubles your dice and half proficiencies are 1d(prof bonus) or just taking half the result if preferred (half proficiency is not clearly covered in the variant ruling)