Looking to overclock a 7770K and was wondering what AIO I can pair it with.
You can pair pretty much any AIO with it. I always recommend the Arctic Liquid Freezer 240 if you have the space for it, cause its price and performance is better than pretty much any 240mm unit, and even some 280mm & 360mm units.
assuming you mean a 7700k, i would reccomend a kraken x62 if your case fits it, great cooling around that price point, i use a Thermaltake Riing RGB 360 and the performance gains over the x62 aren't phenomenal that i've seen.
i would've reccomended the 360mm Predator from EK because it was great after they fixed the leaking issues but they are fazing them out so yeah :-/