Quinn :) fits all. But I would suggest maining a role. In myself main a role now like burst tanks like
all these champs fit similar play styles. The throw out a combo tank up, peel then get the heck out of dodge. yes graves is a bursty like tank with a smokescreen that is light cc. I used to main
and still carry with him and can even play him as ADC i know so much about his gameplay and love it. But you need some diversity and since you get bored like I do try maining like DPS bruiser, backline assassin, DPS ADC, burst ADC, initiating tanks, healing supports, burst mages, hybrid champs etc so many that they can fit any playstyle. I hope this helps. But honestly just play every champ like twice and you will find what fits your playstyle like Quinn is the best ADC for me and I love her in lane but suck bot lane with her so I use MF but she fits basically every role. I try to play champs like Gragas that can go top, mid, jung even sup if i need to due to old ranked system. Playing several roles with one champ helps you learn the kit and roles so much better as well as matchups which is what the whole point a "main" tries to do.