Homebrew Rogue Subclass.

I made this homebrew subclass to try and fill what I thought seemed like a gap in dnd  content.

This gap is characters made to be like Jack Sparrow or The Pirate Captain (both just happen to be pirates).

Characters that get by on the hair on their skin, usually through dumb luck and coincidence.

There as far as I can tell doesn’t have any good options to fill it, the closest I got was with swashbuckler but that felt like it was focused too much on sword combat rather than stupidity/luck. So here is my solution.

Chancer (Rogue)

“Just because I never know what to do doesn’t mean I’m not good at it.”

Level 3: Just might work

You’re great at succeeding… for a little bit.

Whenever you make a D20 test you may, as a bonus action, give yourself advantage on that test and give yourself disadvantage on the next D20 test you make.

Level 3: Accidental acrobatics

You’ve mastered the art of grabbing half dead plants.

Whenever you take damage from falling you may, as a reaction, half the damage you take from the fall. Also whenever you fail an acrobatics check you may as a reaction succeed instead. You may use any of these reactions up to your Chr modifier per long rest.

Level 9: Indirect attack

You don’t miss that easily.

When you make an attack that qualifies for sneak attack and miss you may, as a reaction, deal damage equal to the roll of a number of D6s. The number of D6s you roll is the same as the number of sneak attack dice you have. You may use this ability a number of times equal to your Chr modifier per long rest.

Level 13: Silvery quips

You banter with an edge unprecedented.

You gain the following cunning strike action.

Taunt (Cost 3d6).

The target that has just been hit by your sneak attack must make a Chr saving throw (Dc equals 8 plus your Chr bonus) or gain disadvantage on any attacks it makes until the end of its next turn.

Level 17: Never surrender

You don’t give up that easily.

When you drop to zero hit points you may instead drop to a number of hit points equal to your Chr modifier plus your number of levels in Rogue and then immediately take an action of your choice. You may use this ability once per long rest.

Just Might Work: You should change it from being a bonus action to being a reaction, otherwise it would be completely useless on most saving throws (which usually happen on someone else's turn)

Accidental Acrobatics: A pretty good ability. Would make you very hard to grapple (since avoiding a grapple is an Acrobatics check). I'd change the flavor text though, as it doesn't make much sense for the second part of the ability. Maybe make it something more like "You have learned to make the most of your slips, trips, and falls" or something like that. 

Indirect Attack: Not bad. Helps mitigate those feel-bad moments when you whiff an attack

Silvery Quips: Probably makes more sense for it to be "Disadvantage on all attacks against all targets other than you" like the rest of taunt-like abilities in the game.

Never Surrender: Useful, but a bit underwhelming for a capstone. If you play safe, especially if you are focused on ranged damage, this may become mostly a non-feature. Maybe also make it so you can trigger it yourself, choosing to voluntarily dropped to the specified HP in order to get an extra Action, and allow this action to bypass the once-per-turn restriction on Sneak Attack?

Only other thing I see here is the choice to make them all tied to Charisma. Why Charisma? That's going to limit your usages and DC quite a bit since almost all Rogues are going to want to be Dexterity-based. I would imagine most Rogues would have a hard time getting Charisma higher than +3 until at least level 10 unless they are rolling for stats.

I chose Chr because I was trying to go for a charlatan/maverick kinda vibe to it, but I will keep all your suggestions in mind. :)

I have decided to leave the choice of using Chr for now but I might change it in the future.

So here it is, version 2

Chancer (Rogue) v2

“Just because I never know what to do doesn’t mean I’m not good at it.”

Level 3: Just might work
You’re great at succeeding… for a little bit.
Whenever you make a D20 test you may, as a bonus action or reaction, give yourself advantage on that test and give yourself disadvantage on the next D20 test you make.

Level 3: Accidental acrobatics
You’ve mastered the art of falling with finesse.
Whenever you take damage from falling you may, as a reaction, half the damage you take from the fall. Also whenever you fail an acrobatics check you may as a reaction succeed instead. You may use any of these reactions up to your Chr modifier per long rest.

Level 9: Indirect attack
Just because you didn’t think it hit.
When you make an attack that qualifies for sneak attack and miss you may, as a reaction, deal damage equal to the roll of a number of D6s. The number of D6s you roll is the same as the number of sneak attack dice you have. You may use this ability a number of times equal to your Chr modifier per long rest.

Level 13: Silvery quips
You banter with an edge unprecedented.
You gain the following cunning strike action.

Taunt (Cost 3d6).
The target that has just been hit by your sneak attack must make a Chr saving throw (Dc equals 8 plus your Chr bonus) or gain disadvantage on any attacks against targets besides you it makes until the end of its next turn.

Level 17: Never surrender
You don’t give up that easily.
When you are hit by an attack you may ignore any damage from the attack and instead drop to a number of hit points equal to your Chr modifier plus your number of levels in Rogue and then immediately take an action of your choice. You may use this ability once per long rest.

I’ve underlined the stuff I’ve changed/added.