im no expert but i have two with various tetras, a keyhole cichlid ,bristlenose plecs and corys oh and two female guppies. almost forgot my hoplo, not had any probs.
I have 7 in a 90 gallon tank that live with german rams, bolivian rams, bn plecos, olive nerite snails and rummy nose tetras. There was even a single male krib in there until he died of old age. Zero problems.
I usually keep mine with my females bettas, taking the more placid females and avoiding male bettas altogether. Angelfish like the long fins too much on male bettas, and my males usually nip at the angels fins anyways, driving them slowly insane.
My angel did not get along w/ my DG. Gouramis can be bigger a PITA than (nonspawning) angels.
I agree - anything that's either decently fast or large enough will generally work (Black neons, Cardinals etc have worked so far, though I won't be too surprised if a Cardinal eventually gets eaten when the angel gets a bit larger).
I have kept over the years balla sharks ,black neons, black skirt tetras,glass fish,mollies not by choice (wife and kids thought the tank need more colored fish).
you can keep anything larger than its mouth.
I have Silver Dollars in with mine. I have 2 Silver Dollars, 4 Angelfish, 2 Julie Cories in a 20H. Late they will get moved to a 55. I have no problems as of yet but also don't have a spawning pair.