At level 3, every time you roll a natural 20 in something, you get a luck point. You can SPEND your luck points on different kinds of things such as:

2 - Presence of the fortunate: you may give one of your allies (not yourself) an advantage on the next roll.

4 - Lucky find: Use when making an investigation cheek, add half your rouge level, rounded down, to your roll.

5 - Tricks of fate: Whatever you have rolled is now a critical hit. For example, you can spend your 5 luck points to change the outcome of your roll before or after doing it. If you use this whatever you have rolled is a natural 20/critical hit. 

7 - Unexpected plot twist: You can buy this before or after an enemy has rolled on anything but before the result is soon. That roll is now a Nat 1

10 - Share the luck: Until the start or your next turn, all allies have advantage on up to three of their attacks

Sudden fortune

At level 3

You can do 2 things with that ability 

Lucky dodge: Once per a long rest, you can use your reaction to luckily dodge any attack, however you have to make a dexterity saving throw with the DC of 14, if you fail you fall prone. At level 14 this ability regenerates from a short rest.

Or

Beginner's luck: You can get advantage on any ability check which You don't have proficiency or expertise in. You can only use it once, but it regenerates after a long rest. You don't get advantage on saving throws. At level 14 this ability regenerates from a short rest.

At level 3

A number of time equal to your chr modifier per a short or a long rest you can use this. After you roll a D20 or something in eyesight rolls a D20, before the outcome is reveled, you may reroll that D20 and must take the new roll,