Several fish will do well as tank mates for cichlids, wise selections are Synodontis catfish, Botia Loaches, Labeo Sharks, larger Rainbowfish & Danios, suckermouth catfish (Plecos) and the larger Tetras.
Cichlids are very difficult fish because they are aggressive or, sometimes, semi-aggressive. I have some tinfoil barbs nothing bothers, and I also have buenos aires tetras that all the aggressive fish ignore. There are certain bottom dwellers they will ignore, too. Try discussing the cichlids you are choosing with knowledgeable store help.
The best tank mates for cichlids are more cichlids from the same great rift lake/region. It is also important that they are similar in size and that there are adequate hiding spaces for all of your fish so that their aggressive nature doesn't result in fatalities.