Martial archetype : The Gamester

Gamesters are fighters that use their fighting skills to push encounters into states of gamble. Chance greatly affects these fighters, though not all of them are aware of it. Everything is a game of luck; and Gamesters often force lady luck's hand.

Cross and Pile Starting at 3rd level, you can use this feature before knowing the outcome of a contest roll, skill check or saving throw to choose a coin's side and flip it. If it lands on the chosen side, add 1 to your roll (this becomes 2 at level 15). If not, subtract that value from your roll instead. After flipping your coin, you can choose to do so again. If it lands on the same side as the first flip, it's effects are doubled. If not, it's effect is removed.

Game Fanatic Beginning at 7th level, you choose one favorite game from the Favorite games list and gain it's feature. You gain an additional one at levels 10 and 18. When gaining an additional game, you can also choose one of your favorite games and replace it with another. Additionally, you gain proficiency with a gaming set if you've played a Tavern game with it at least once.

Passe-Dix At 15th level,, after failing a skill check or saving throw, you can use this feature to choose High (above 11) or Low (below 10), and roll 3d6. If the result matches your choice, you can consider your roll a natural 20. If it matches the opposite choice, you consider your roll a natural 1. If the result is 10 or 11, nothing happens. Whenever you use this feature, you must use the result's value for your roll. You can use this feature a number of times equals to your Charisma modifier. You regain all expended uses after a long rest.