Welcome!
I don't commonly use crankbaits but I've caught some of my nicest ones on 3" fat raps. I think a lot of guys use Bandit crankbaits and troll for them, in the 100, 200, and 300 sizes, depending on how deep they are.
Colors can be hit or miss. If I were going to go buy a bunch, I'd get some whites, black back and white body, dark green back white body, and some bright colors if they're available.