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?
If I had to answer my own question, I'd probably start with the patron deities of the five longest-running playable nonhuman species:
1) Corellon Larethian (representing elves and half-elves)
2) Garl Glittergold (representing gnomes)
3) Gruumsh (representing orcs and half-orcs)
4) Moradin (representing dwarves)
5) Yondalla (representing halflings)
I would also include at least one dragon-themed deity on the list, possibly:
6) Bahamut
7) Tiamat
To the above, I'd probably add at least two fiends who have ascended to godhood:
8) Lolth
9) Asmodeus
Orcus was temporarily a deity, so he could arguably be added to the list. Demogorgon would be on the list if he were an actual deity, but I don't think he ever was.
I'd probably also include two evil deities who've shown up in multiple settings throughout the D&D multiverse:
10) The Elder Elemental Eye (though I don't know which of its proper names I'd use, if any)
11) Vecna
Too make it an even dozen, I'm inclined to add Annam All-Father, progenitor of giants and titans, but I'm not sure he's sufficiently iconic. Also, he's mostly retired from the world, having been more-or-less replaced by his even less-iconic offspring. The most powerful of these are Haitea and Stronmaus, neither of whom gets mentioned very often.
That's my answer off the top of my head, but I'm not 100% committed to it. What would your choices be?