When looking for what motherboard supports that processor, you'll need to check the motherboard's supported CPU list from the manufacturer. Some motherboards will need a BIOS update to support that processor.
Like the other guy said, it's got an 1150 socket, so you can check websites like Newegg and PC Part Picker for motherboards that have that socket. PC Part Picker is pretty good at telling what's compatible or not, so I'd start there, pick that CPU, then see what motherboards it lists as compatible.
I don't really know about overclocking, I suspect it's the chipset and what sort of cooling the motherboard has. You can probably search for guides that tell you have to overclock the i7 4790K and tell you what to look for in the motherboard.