Nasus pushes pretty good-
Either the constant smashing of siphoning strike into the minions pushes,
or spamming spirit fire.
Built with a moderate amount of ap- nasus pushes REALLY FAST using spirit fire.
You need to level it if you want to kill creep waves.
The big problem- both siphoning strike and spirit fire burn mana super-fast.
Ap yi pushes quite fast, but you don't insta-level minion waves.
You could do it as ap/madreds-razor hybrid though. (I like bloodrazor)
You want to farm both the lane, the blue buff, and then your enemies jungle. Then go back and farm the lane
Cho can level minion waves with a combo of spikes and rupture. He has the potential to be the fastest farmer, mid-game, I think,
but that means delaying tank items.
As jungle cho, I have had better-than perfect cs midgame.(Compared to just laning)
While I did farm lanes people weren't in, I really impressed somebody playing corki.
atmas/wits end/guinsoos? not sure if ap, or as/ad is better for farming.
Galio can wipe out caster minions midgame maxing resolute smite and gust
Sejuani's pushing power is probably ok.
Gragas barrels push hard. Great midgame-farmer.
Trist pushes naturally. Hybrid is probably the best pusher.
Heimer, of course!
Ziggs is competative with ap malz on pushing, only a little bit behind.
And so much range! Farming is best with minefield I think.
Ap zil could wipe waves, but you still need mana, or constantly going b(which is viable with time warp).
Also ap zil isn't that useful. His nuke is much weaker than others.
Movespeed helps. I get swiftness on ap yi so I can farm anything and everything, Then enter teamfights at a leisurely pace.