Has it just not come out yet? I can't seem to find a main. My friend's favorite champion came out recently (Bard) and has basically played him nonstop since. I can't seem to find mine though. Any reason why?
Maybe you haven't tried out each one enough times to come to a definite conclusion? Not liking a Champion's thematics is just one part of the equation; play around with different kits for a while and see if there's one you come to enjoy.
Are you not liking what? their lore, their mechanics their personality?
Not everyone latches on to a champion and just like variety.
I have a short list of champs that I like to play for a week or so at a time and then on to the next.
Yeah, so. It took me a while to find out what I liked. I thought it was burst mages. But you have to play a couple different games with each champ and see what their "niche" is. Like....
Peel in human form, Assassinate in cougar form.
Combo based in bursting. E,W,E,R. Zoning with plants.
Skill, AA, Skill, AA, Skill AA for full passive effect.
It takes a while, but that's how you see what play-style you enjoy.
Could be that one will be released eventually that you like. I was in the same boat as you, couldn't find a champion that I really liked. Then Nami was released, and I found that I adore her.
I would suggest zac. Everything about his kit feels satisfying after you get the feel for him. Yeah, he's kind of hard to actually get used to but landing an e engage on 2-3 people is an amazing feeling. :)
Well you know what they say.
There's just no pleasing some people. :P
You could always play 
. It's pretty fun imo.
Sustained aoe damage (with cdr), waveclear, range, assassination potential, hard cc, healing passive, can peel for carries with rylais, can engage with zhonyas, mobility and the best skins ever.
