Luckster

You are naturally lucky, and become luckier and luckier the more you fail. 

Pool of Luck

Starting at 3rd level, you gain a pool of Luck points that fill when you fail at a task. Every time you fail on an ability check, attack roll, or saving throw, you gain a Luck point. Your maximum number of Luck points is equal to your proficiency bonus. 

Whenever you make an attack roll, ability check, or saving throw, you can expend any number of Luck points you have. For each Luck point you expend, add +1 to that roll. You do this after you see the result of the roll, but before the DM says whether or not you succeeded. 

Any unused Luck points are lost at the end of a long rest. 

Bonus Proficiencies

At 3rd level, you gain proficiency in 1 skill and 3 gaming sets of your choice. Any ability check you make with a gaming set is made with advantage. 

Share the Wealth

Starting at 9th level, when another creature you can see within 60 feet of you makes an attack roll, ability check, or saving throw, you can use your reaction to expend any number of Luck points. For each Luck point you expend, add +1 to that creature’s roll. You make this choice after you see the result of the roll, but before the DM says if it succeeds or not. 

By the Skin of Your Teeth

At 13th level, when you would be reduced to 0 hit points and you have any Luck points, you can use your reaction to expend all of your Luck points and be reduced to 1 hit point instead. 

Once you use this feature, you can not gain any Luck points until you finish a long rest. 

Lucky Defense

When you reach 17th level, you gain a bonus to your AC equal to the number of Luck points you have.