Hi Paul, welcome to the forum.
I started my first African tank in the spring with mbuna. I asked the same as you, and in my opinion, took good advise. I stocked a 55 with yellow labs, rusties, cynotilapia zebroides 'Jalo reef", and otopharynx lithobates 'yellow blaze'. You really can't go wrong with rusties and labs. The otopharynx, not actually mbuna, are growing a bit big now for a 55, but are otherwise non-aggressive, and work in well with the rest. They are slower to color up tho. The Jalo reef are really cool, but the most aggressive of the bunch,but that aggression is reserved for each other.
As Tony said, do a little searching, and see what you like. Dave's Rare Fish has a great selection, with pictures of each for quick reference. Pick out a few that you like, then ask the forum if they will work together. Best of luck