Let's say you're making a world-agnostic pantheon of deities, and you want to include all the big name deities of D&D. What deities would you include in that pantheon?
Off the top of my head as the A-list:
1: The Raven Queen. Blame Critical Role - and a lot of writing for her.
2: Tiamat (inc. Takhsis). She's iconic, especially thanks to strong visual imagery.
3: Vecna. Looks iconic, has iconic artifacts, and is pretty famous.
4: Lolth. Again strong visual aesthetic and known for stuff including the Drow.
5: Asmodeus. The iconic demonic deity.
6: Gruumsh. The God of Orcs is simultaneously a deity with a common enemy, someone with an appropriate ideology, and has a fairly iconic look. More low key than the previous ones.
It is not a coincidence that most of these are evil deities; people spend more time facing bad guys than dealing with allies. Also there's iconic imagery attached to them.
Other possible adversaries:
1: Demogorgon. Blame Stranger things for this - but if we want the "classic" Blood War we need a lead demon as well as a lead devil
2: Tharizdun. A world ending threat; the Chained God is the iconic one.
3: Magublyet. The god of goblins isn't as iconic as Gruumsh but misses out.
4: Blipbloppool. We ne3ed a lesser evil deity - and it's fun to say!
Other possible patrons:
0: Mystra. I suppose we have to mention Ed Greenwood's fetish and the Lady of the Weave. But I wouldn't want her.
1: Correlon. The God of Elves has a relationship with Gruumsh. He's about the only good racial deity that makes it, especially as we have both Lolth and Gruumsh.
2: Bahamut. The Platinum Dragon definitely has a place as a rival to Tiamat. Probably makes it in over Pelor.
3: Erathis. The Lawful Neutral Goddess of Civilisation
4: St. Cuthbert of the Cudgel. Because we need a Hitty Deity.
We also need more of a trickster.