Twitch was my main season 3, and he seems to be getting back into the top of the tier list. I'm 5/0 (W/L) with him in ranked games, with 4.5:1 KDA, and my last Penta was with him.
Tried Fizz AD ranked some times, but even performing well, he doesn't have the potential to carry, but it's still as useful as AP Fizz.
Some are squared feet, but here's the list of some:
Alistar, Amumu, Cho'Gath, Corki (no feet, tho), Mundo, Galio, Malphite, Mordekaiser, Miss Fortune, Nunu, Pantheon, Poppy, Ryze, Shaco, Shen, Singed, Sion, Taric, Tristana, Udyr, Urgot, Veigar.