Catfish like almost any type of minnows, cutup fish, worms, and even corn. I've caught many on simply corn and its a simple and cheap bait to get. Bigger whole kernel corn that fits better on hook. Bait like crawdads and frogs and stuff like that works also of course, stink baits work well (but are messy), and hot dogs even work but I havent tried those (no reason to).
The dumbest baits I've seen used are these that spray wd-40 oil on the bait, and a catfish bites it (which they would have without the oil), and they proclaim I FOUND A GREAT CATFISH SECRET! Its literallly the dumbest thing I've ever seen.