There are other pantheons which have not made it into the AD&D game (or, not to a significant degree). Deities from some of these pantheons have been mentioned on occasion, however. I don’t have sources on most of these pantheons at this time (other than Hittite), but there’s definitely some interesting potentialities among them. Much of my current knowledge is from books on other topics that just tangentially touch on these pantheons. Of these, the Hittite pantheon is one I would certainly be working on at some point, while most of the others are far less likely
Slavic Pantheon, an Indo-European faith mostly known from Christian writing:
—Chernobog
—Perun
—Stribog
—Svarog
—Svarozhits
—Veles
Baltic Pantheon, an Indo-European faith mostly known from Christian writing:
—Perkunas
—Velnias
Hittite/Hurrian/Hattian, peoples of Anatolia; the Hittites were Indo-European but much of their faith was drawn or adapted from the earlier, unrelated Hurrians (who may be related to the Urartians) and Hattians, as well as drawn from Mesopotamia:
—Hannahannah
—Kumarbi
—Shaushka
—The Sun Goddess of Arinna
—Tarhunna/Tarhunt
—Teshub
Elamite, the religion of the peoples of the Iranian highlands east of Mesopotamia and the great rival of the Sumerians. Little is known of their pantheon, however.
—Inshushinak
—Kiririsha
—Napirisha
—Humban
—Pienenkir
—Nahhunte
West Semitic/Canaanite/Phoenician mythologies, all closely related to each other, and related to the mythologies of Mesopotamia, these faiths were the people of the Levant and eventually Phoenicia. Many of them are prefixed with Ba’al, which means Lord. Many of the deities entered Christianity as the names of demons.
—Aglibol
—Astarte
—Ba’al Hammon
—Dagon
—Melqart
—Yarhibol
Persian/Zoroastrian, the ancient Persian religions show some close similarities with the ancient Indian pantheon of the Rig Veda, with Zoroastrianism being a direct outgrowth of it.
—Ahura Mazda
—Mithra (popular among Romans, as well)
—Ahriman (Guide to Hell indicates Asmodeus is actually Ahriman)
African Mythologies, detailed in Dragon Magazines #191 and #215; multiple different mythologies are merged into one much as the Celtic pantheon did.
—Ala (Dragon #191)
—Ananse (Dragon #215)
—Antelope Man (Dragon #215)
—Asase Ya (Dragon #215)
—Bumba (Dragon #215)
—Cagn (Dragon #215)
—Chameleon Man (Dragon #215)
—Eshu (Dragon #191)
—Gauna (Dragon #215)
—Khonvum (Dragon #215)
—Leza (Dragon #215)
—Lion Man (Dragon #215)
—Nyame (Dragon #215)
—Obatala (Dragon #191)
—Olokun (Dragon #191)
—Olurun (Dragon #191)
—Orunmilla (Dragon #191)
—Porcupine Man (Dragon #215)
—Shango (Dragon #191)
—So (Dragon #215)
There’s certainly many more pantheons and faiths out there, but I know them even less than these! I’m always up for investigating these other pantheons, however.
This book mentions a lot of deities and supernatural beings, from many cultures. I took the name Barastir from it: https://www.taylorfrancis.com/books/mono/10.4324/9781315002385/dictionary-gods-goddesses-devils-demons-manfred-lurker
Have you considered the pre-Islamic Arabian gods? Not a lot of resources out there for them, though, plus the list is huge. I was looking at it on Wikipedia. You could also try redoing the Al’qadim pantheon, giving them proper entries.
Yeah, it’s on the list of potential pantheons!
I dunno that I would want to do anything with Al Qadim, I don’t know the setting well enough, and it intentionally has a unique religious system. What I would prefer is putting them into Planescape.
Here’s a crazy idea: what about the gods of Mystara? Yeah, they’re actually “Immortals,” but that distinction was dumped toward the end of AD&D 2E, which is why the good and neutral deities of Mystara are in the list of gods at the end of Warriors of Heaven. It’d be nice to finally see them get proper 2E presentations!
Alternatively, what about the gods of Tellene, from the Kingdoms of Kalamar setting? The original boxed set gave them a 2E-style presentation, albeit an antiquated one, and we later had 1E/2E stats for them in Hackmaster’s Gawds & Demi-gawds books. (The latter also had the pantheon for the Hackmaster setting’s word of Aldrazar.)
I don’t feel I know Mystara well enough to do it, really, and I’d probably want to do Greyhawk before I touched it. I guess it’s a similar amount of research, but right now I’m more interested in races that haven’t gotten enough information or real-world pantheons. :)