My Top 5 Sleeper OP Champions

Meh, Kog'maw is anything but sleeper right now, AD and AP log are both very strong picks and see a fair amount of competitive play.

Galio is definitely sleeper OP, not so sure about nocturne, Vel'koz, and Zyra.

Totally agree on Galio. He absolutely destroys any AP champ and he does well against the AD ones too. Zyra would def be OP if Riot ever fixed the targeting AI on her plants. With the new buff Noc is getting, he will be very strong. Vel has always been strong, but not necessarily OP. AP Kog is def OP, but most people know that, so he isn't a sleeper.