The ones I'd suggest differ depending on the cichlid you want... Angelfish have a tendency to kill smaller tankmates, while Rams or Kribs are much more tolerant.
If you go with Rams or Kribs, you might want to consider dither fish to help them feel more confident so they can show their full colors and personality. Dwarf rainbows (threadfins are my favorites, but there are several types), cherry barbs, and danios are all good options and tend to be small enough that they won't usually pick off any fry if the cichlids breed (though the danios may try).
If you go with Angelfish, you'll want larger fish and/or very fast & nimble fish that can stay out of the Angel's way if it decides to take a nip at them. Larger Tetras (Black or White Skirts work well), Pencilfish, or Killies work well with them.