If you are set on an angelfish tank, be wary of overstocking. A long time ago, I made that mistake in a community tank with angels as the focus. Personally, I would go for tankmates that occupy a different part of the water column. Angelfish can be territorial jerks sometimes. Your options are limited with a 36 gallon tank, but many species of corydoras catfish would be a good fit. You may be aware already, but they like to shoal and prefer sand to gravel.
Avoid most barbs (except maybe cherry barbs) and be careful with certain tetra species. Some are small enough that adult angels will eat them (ex. neons) and others are known to nip fins (ex. black skirts) especially if their shoal is of insufficient number. I, myself, keep black skirt tetras with my angelfish and they've been peaceful. However, my tank is much larger, sustaining a sizable shoal and enabling the angels and tetras to put distance between each other.
I keep a bristlenose pleco in that same community tank which might work for you. They have specific dietary requirements but are, overall, not difficult if you do your research. They'll also consume algae and don't grow as large or aggressive as many pleco species (avoid those). The angelfish will probably ignore this fish completely.
Some people have had luck with angels and dwarf gourami but I would hesitate to keep both in a smaller tank. Also, be careful where you source dwarf gourami as terrible breeding practices have made many of them rather frail.
You probably know this already, but I'm not suggesting you add all of these fish simultaneously. Stocking 2 angels, a shoal of Cory cats, a shoal of some tetra species, and a bristlenose pleco in a 39 gallon tank is beyond inadvisable (especially considering the adults size of some of these species).
What shape is your tank? More vertical or horizontal? Horizontal tanks can generally support more fish but the shape of angelfish lends itself well to a vertical tank. Furthermore, you could just keep the angelfish pair without any tankmates. It would take pressure off the system and you could specialize your setup for that species without worrying about the requirements of any other fish.
All else aside, best of luck. If anyone else has suggestions or has kept angelfish in something between 35 and 40g, chime in!