My first suggestion is to increase two of the fish you now have, namely the hatchetfish and the corys. Both will be much better [= healthier] with several more. I don't know which species of hatchetfish you have, but with all of them you can never have too many--but don't overcrowd the tank.
If you have one of the species in Carnegiella, definitely no less than 9 and much better with 12+. If it is the larger common silver hatchetfish, I would say 7 is minimum, but in your tank I would have 9.
Corys, must have more. You've space for a group of 15-20, which can be various species so long as there are several of each species. I try to have five of a species, though often 3 is the minimum when there are more than the one species.
Then, beyond that, to other tankmates. With angelfish you want quiet, non-active fish, and only those than are not likely to fin nip. Some of the best come from what we call the Rosy clade in Hyphessobrycon. There are several species in our profiles (use the scientific name index and look at those in Hyphessobrycon). These work because they are disk-shaped, like the angels, and thus not likely to be eaten as linear tetra will. Just avoid the few nippers, some are deadly. There are two that stand out because of their reddish colouration which is a nice contrast to the silver/black of angelfish; Hyphessobrycon rosaceus and Hyphessobrycon bentosi [click shaded names for the profile]. Hemigrammus pulcher also works, if you can find them, they are not all that common; and Hyphessobrycon pulchripinnis is another nice contrast with its yellow hue.