Not disagreeing that these will probably never be kept by hobbyists, so this isn't super relevant to the topic at hand, but we currently have the tech to keep moderately deep sea (Bathypelagic - ~5,900ft) creatures with things like the Abyss Box* so it wouldn't surprise me if we ended up with the tech to keep super deep sea creatures at some point in the next decade or two.
*
https://en.wikipedia.org/wiki/Abyss_Box
Yeah, the only reason I personally like to specify Aquilonastra vs Asterina is because Asterina is actually a genus of Asterinidae on its own. We pretty much all know what is being referred to when the term Asterina is used though, so I don't particularly care when the term is used even though it's technically misleading.
I do have to agree, most people don't know to spot feed starfish (in fact, a lot of people don't realize that their CUC needs fed too).
Now, to answer the original question of this thread (some of these may have been listed elsewhere in the thread, and I know I'm forgetting a few, but I can't remember which ones - also, a lot of these are coldwater stars):
-Blue/Colored Phataria Starfish (Phataria unifascialis)
-Burgundy Sea Star (Tamaria [?] sp.)
-Granulated/Doughboy Sea Star (Choriaster granulatus)
-Dalmation Sea Star (Linckia multifora* - technically, according to DNA studies, Linckia multifora and Linckia laevigata are considered ecophenotypes of the same species, Linckia multifora)
-Purple Linckia Star (called Tamaria stria - actually Linckia columbiae)
-Spotted Starfish (genus and species unlisted - possibly Echinaster sp. or Asterias sp., but I'm not certain)
-Pink Lace Starfish (Echinaster sp.)
-Black Linckia Starfish (genus and species unlisted - presumably Linckia sp.)
-Orange Starfish (Echinaster spinulosus)
-Spiny Sand Star (Luidia alternata)
-Gray Sand Star (Luidia clathrata)
-Pointed Sand Star (Astropecten duplicatus)
-African Starfish (Pentaceraster sp. or spp.)
-Red Biscuit/West African Biscuit Starfish (Anchitosia queenslandensis)
-Black Chip/Chocolate Chip Cushion Starfish (Nidorellia armata)
-Cortez Sea Star (Pentaceraster cumingi)
-Komodo Rainbow Sea Star (Gomophia gomophia)
-Burgundy Linckia Starfish (Linckia sp. or Echinaster sp.)
-Sand Sifting Starfish (Archaster typicus)
-Honeycomb/Cushion Starfish (Pentaceraster alveolatus)
-Crown of Thorns Sea Star (Acanthaster planci - this is actually sold in some places, I wouldn't recommend keeping it, but you could actually keep and breed these if you really wanted to if you lived in the right place; I'm not sure about the legality of keeping one here in the US)
-Hefferman's Starfish (Celerina heffernani)
-Striking Sea Star (Eureaster insignis)
-Egyptian Sea Star (Gomophia egyptica)
-Red Cushion/West India Sea Star (Oreaster reticulatus)
-Regular Sea Star (Pentaceraster regulus)
-Vermillion Sea Star (Pentagonaster dubeni)
-Mosaic Sea Star (Plectaster decanus)
-Horse Star (Hippasteria phrygiana)
-Northern Sea Star (Asterias vulgaris)
-Forbe's Sea Star (Asterias forbesi)
-Blood Star (Henricia leviuscula)
-Purple/Smooth Sunstar (Solaster endeca)
-Spiny Sunstar (Crossaster papposus)
-Brood/Slender Star (Lepasterias spp.)
-Sunflower Star (Pycnopodia helianthodes)
-Ochre Star (Pisaster ochraceus)
-Short Spined Sea Star (Pisaster brevispinnis)
-Fragile Rainbow Star (Astrometis sertulifera)
-Giant-spined Star (Pisaster giganteus)
-Bat Star (Patiria miniata)
-Spiny Sand Star/Estrella de Arena (Astropecten armatus)
Edit: also, there are a few Echinaster and other commonly seen genus stars that I just skipped listing because there are a ton of them available.