Lucky Bastard

As a Treant hurls a massive boulder towards the party, the dexterous rogue passes his save with ease. However, looking to their right, he sees the party's not-so-dexterous dwarven cleric, staring as her life passes before her eyes. The Dwarf has already taken enough hits, and a boulder of this size could easily overkill. The rogue smirks. He's confident. He negates his own passing roll, imposing advantage on the dwarf's upcoming save before rolling, and succeeding, once more. The rogue player smiles and glances at the dwarf, who is preparing to roll her save with newfound advantage. A 14, after both rolls. The rogue grits his teeth. It might not be enough. He prepares to save his luck for himself, but a dead healer is always a bad sign. He spends two points strokes of luck, and the dwarf's save ends up at a sixteen. The DM smiles and informs the Dwarf that she barely passed. The rogue player leans back in his seat, smiling. When you've got this much good luck, you may as well spread it around.

Luck for Later

You have luck points equal to your rogue level that replenish after a long rest. You may use a point of luck to add or subtract from specified rolls by one as many times as you like and are able. No matter how many luck points you use, this counts as a single reaction. Raising an ally's roll to a twenty does not incur the benefits of a crit, but lowering an enemy's roll to a one incurs the detriments of a crit fail, whatever the dm decides they may be. You are also unable to use your luck to affect critical successes or fails.

Overflowing Luck

Starting at 3rd level, you may reroll any check you succeed, and impose advantage on an ally's roll. This ally must be making an ability check, attack roll, or saving throw. If they are making the same roll as you simultaneously (ie: to dodge the same attack) they may also add 3 to their roll.

Ace in the Hole

Whenever you take a short rest, write down an ability and place it somewhere it cannot be tampered with. The first time you or any member of your party must make a check of that ability, reveal it to the rest of the group. Whoever is making the check makes it with advantage. If the check is done by several players simultaneously, they all gain advantage.

Not Wasting that one

Ever roll a natural 20 on history and wish you could use it in combat? From now on, once per short rest you may choose to fail a roll if you succeed, and use the succeeding roll later.

Risky God Rolls

When you reach 17th level, 1-3 now counts as a critical failure, and 18-20 now count as a critical success. You may spend three Luck points to reroll a critical failure.