As has been said, the pantheons that aren't specified as belonging to a specific race are really human deities most of the time.* This basically allows you to represent a variety of human gods and pantheons in your D&D experience. Since most players are presumably human, there are a lot more of these and they make new ones for most settings.
Since we don't have any elf players, they can generally settle for one D&D "elf pantheon" and call it good.
One of the cool features of the shared non-human pantheons is that it serves to bind the multiverse together better. The same applies with the archfiends and such (and there are archcelestials, they just don't get as much screen time). If utilized, this allows for more of a shared world feel, even if your home campaign world is completely home brew. I think that's awesome--being able to create your own thing, but still be a part of the D&D multiverse. You get both individuality and belonging in a way you don't get if you homebrew your entire cosmology, or use a published setting massively altered.
To take it further, there actually are some human pantheons that are considered very common in the multiverse--their presence is found on numerous different worlds. Those are the fantasy historical ones. In fact, Planescape says that there are 5 "great pantheons" which are considered to be the most powerful/influential/widespread in the multiverse. These are (as I recall), the Elven, Dwarven, Greek, Norse, and Celtic.
* This is why I strongly disfavor non-humans worshipping human gods outside of exceptional circumstances (or a world where all races worship the same pantheon). In general, it would be some sort of cultural treason for a dwarf to worship a human deity instead of the dwarven pantheon. What, your own gods aren't good enough for you? It doesn't make a lot of sense. The fact that they sometimes have this be a thing is a flaw in the pattern to me, though I think it is usually applied when they want simplicity in presentation for some editions or products. So instead of presenting each racial pantheon, they'll just present the leader of the pantheon, and if your dwarf doesn't really fit Moradin, you just pick one of the "general" deities instead. It's understandable, but I still believe it's a bad simplification they should have never presented. If you need a sample pantheon without racial distinctions, use one of those (the game has multiple such pantheons). Don't pretend a human pantheon is really just a general one. All that being said, I will admit that D&D presentation of humanity gives reasonable credit to the idea that human deities might be more adaptable and willing to accept worshippers from a variety of races.
