champs to play on low tier

please note that this is just based on my opinion
Fiora:
A really strong duelist, can almost win every 1v1 due to her skill set, easy to use, need a perfect timing on her E.

Cho Gath:
Tanky, deals true damage, silence, knockup, very great sustain. Just be good in laning phase and get strong late game!

Darius:
Use his strong kits to get an early game boost! Easy to get fed early on laning phase, very simple to use, could win 2v1 easily when u hit 6, need a smart use on his Q.

Syndra:
Her R can delete squishy targets extremely fast! Use it early to kill their carry on a teamfight to get a 4v5 

Fizz:
I'd say the most perfect champ to climb elo. Very high damage, can chase/escape really easy.

Rammus:
Really good jungle pick against strong DPS, easily taunt the DPS dealer on team fight and win.

Twitch:
Safe with his stealth, just stand back, ult and finish up the enemies. But dependant on your team's tanker and initiator.

Vayne:
Very very easy to use, really good at kiting and chasing, strong against tanks. Need good positioning

Darius is good for agressive players, you can play 2v1 at level 1, watch out for Yorick and Illaoi (your counters, ban'em)

I think Ragnaros is really fun, although it depends on your playstyle

good, but you dont writed how you are speaking lol champions.