What type of fishes can I put with cichlids?
It depends on the cichlids and on the fish you want to keep with them. Some fish like mbuna's can only really be kept with other cichlids or a very few other fish. Dwarf cichlids however are generally more tolerant and won't bother other fishes. I have two rainbow cichlids in my tank with guppies, neon tetras and hillstream loaches and haven't had any issues. I would advise caution though if you have a breeding pair as they can be seriously aggressive when defending their young. What sort of cichlids were you considering?
Some Cichlids (depending on the type of course) can be kept with some of the larger barbs and plecos. Mainly fish that can really hold their own.
I have two Bolivian Rams with a female BN pleco and cherry barbs(among other fish), they do just fine together. Welcome to the forum!