How big a tank. Tetras, L numbers, some apistos, uaru, stingrays and smaller gymnotids like black ghosts all make for good displays.
I've kept mine with angels (shock) , tetras, apistos, black knifes (gasp) and horror of horrors other cichlids! Geophagus, acarichthys !
I'm sure if you really want to breed discus it makes sense to go bare bottom and discus only, but I really don't believe they're as fragile as people make out. The most stunning displays I've seen have been big tanks with big shoals (10+) - then they're not shy and not unaggressive.
Rams for me are right out as they are NOT biotope correct at all.