Kinda ignoring the current meta who are some good multi role champions to one trick/main? I really want to limit my champions and practice some that have a bit of skill, but not have to worry about getting an off role. Would prefer not jungle.
can be anything, even a support
I think Ekko is a good one.
He can be very strong both top and mid, and even jg if you do happen to get stuck with it.
He also has a pretty high skill cap and is versatile.
He currently has the lowest win rate as a support yet he is a support. He has higher win rates in top, jungle and mid.
He can function as a support 
, a tank 
, or a fighter 
Kayle has really bad first clear in jungle though
Pyke if you're willing to put in the extra effort. Taric, though I haven't done much with him this season so I can't say whether or not the versatility still exists. Twitch, I've found, is great with ADC Jungling or Mid depending on how you want to do things. I've been seeing a lot of Quinn all over the place. I've done well with Yorick, Swain and Urgot in at least 3 positions each.
jg/mid, might be the hardest scaling ap champ in the game, satisfying af to play.
jg/top
mid/top/jg
mid/top/jg (mid/top better picked into an AP enemy laner)
Mordekaiser can play literally everywhere in the game. 
ekko diana mundo yasuo aatrox jax lee karthus olaf qiyana nasus quinn neeko tryndamere camille udyr sylas rumble riven
maybe missed a few who knows. each should be able to perform at least 4 roles if you care to learn them.
