League of Legends (LoL) Question: Best split pushers mid and top?

Tryndamere top is the best by a longshot. I'd probably say Shen, Fiora and maybe Pantheon top as close second place.

Most mid laners aren't good splitpushers for the very reason they're in the mid lane: They don't have good mobility. Some exceptions could be Kassadin and LeBlanc, since they get most of their mobility in mid-late game, so they're in the mid lane even if they're very mobile solely for the early game safety.

IDK if I'm forgetting someone. EDIT: Nasus top somewhat, but he's tricky.

Side note: AFAIK getting Teleport is mandatory if you're going to splitpush in order to appear if a teamfight happens and you must be there (DO NOT use it to go to a pushed lane, someone is going to come and you will waste your tp and risk getting killed).

Quinn. Once you get Runaan's hurricane, if you want to splitpush, she's has a fast clear and insane mobility to get to any lane, push, and leave before anyones any the wiser.

Top lane? Tryndamere and Rek'Sai in my opinion ;)

Top: Nasus or Jax

Mid: Zed or Kata ^^

Nasus top by far for me, and i have found diana being very good for pushing in the mid lane, especially if you buy lich bane and/or nashor's tooth. :)

IMO Fiora is one of the best top laners to split push with

AP Ekko is a super great mid lane split-pusher, since he's got great waveclear with his Q, good damage on towers with lich-bane and his E, and he's a good duelist. Plus with his E and ultimate he's really good at running from people! Sort of like Zed, but more flexible.

Don't forget about Trundle. With botrk he melts turrets like crazy.

zzrot my best bae for split p