Hey.
I wanna one trick a champion to climb next season, but I don't know who to choose. I like fast paced fighters/bruisers with higher skill ceilings, usually top laners. I also really like being able to punish my enemy laner for their mistakes or mispositioning.
Other plus sides are spit push ability, lane sustain, mobility, and blind pick ability.
Any suggestions?
,Always !
[garen-swing]
Thresh. Always thresh.
Lots of ways to play him
One of the highest skill ceilings in the game- directly from riot.
Punishes out of position players.
Split push? how about proxy 2 or even all 3 waves in their base
Mobility? Passive + 
+ Ult + 
+ 
Bonus: tilt other players out of their minds
The correct answer here is to pick a champion you find fun, that way you don't get tired of them half way into the season. That would be the worst thing, not wanting to play the champion you have the most practice with.
As to which champion to pick I'd suggest one that will teach you the most, that way as you're grinding out LP you're also improving as a player. As SaturnSC1 said Garen is a great choice, though he didn't say why. Being a low mechanical skill champion he allows you to focus on your macro play, which is something you carry between each and every champion and lane. You saying you want a fast pace makes me think you'll prefer mechanical champs over game knowledge champs, so I doubt you'll pick him, but at least consider it.
For a list of other champions to look at try Camille, Urgot, or Kled. They are far enough from the current meta that they could go a long time without seeing changes, but not so far that they their mains are doing poorly at the moment.
Really one tricking is something where the champ chooses you, if you're torn between multiple champs you're probably going to have a bad time playing just one.
I'd recommend trying most fighters/bruisers while on free week (or just from buying them) and see if any of them naturally stand out to you as something that just felt really 'right' for you.
Of the top of my head, jax fits a bunch of the criteria you mentioned imo, but again, try most tops first, since sometimes things that sound good on paper just don't click, and thigns that maybe don't sound like your jam really jive with you once you try them.
(Also, in case it comes up or it's a concern to you, don't worry about what is meta or not currently. Provided your goal is not higher than diamond, it doesn't matter what you one trick, since the idea of one tricking is to actually get good at the champion and being able to outplay people with it, rather than just ride a champ because the champ is good even if you aren't.)
Fits pretty much anything but the mobility
Fits everything but is frustrating to play against Tanks with their bramble vest
Fits everything but again, frustrating to play against bramble
Fits pretty much anything but the mobility... kinda? unless you count his ult as mobility. Has some good 1 v 2 potential
Fits everything but the sustain, you have sudo-sutain with shield i guess against poke champs
Just like Fiora and Rene, frustrating to play against bramble
kinda an AP Bruiser, tho splitpushing and punishing your enemy is hard, also has low mobility
Can be picked into pretty much anything and win lane. is EXTREMELY frustrating to play against bramble/exe. Low mobility and punishing your laner for misspositioning is kinda tricky. If you successfully punish your laner he will propably lose 60% of their hp but they have to fuck up hard for you to punish them.
Has no sustain
Cannot be picked into everything and has no sustain
Fits everything
Has no sustain and pushing power is weak
Has sudo-sustain with skarl but fits everything else
These champs would be the ones I recommend you
Edit: If you have a question or want to know why exactly I included that champ just ask. I just explained kinda shortly on why these champs are here.
