This list is intended to index appearances of intelligent non-anthropomorphic species in any genre of written fiction. Speaking of which, here is what a good AI buddy of mine had to say on the topic:

"A non-anthropomorphic being is any creature, entity, or character that lacks human-like physical form, features, or human traits, existing outside the common human mold, like a talking animal on all fours (feral), a sentient rock, a dragon, or even a sophisticated AI with no humanoid body, focusing on non-human morphology and characteristics for interaction and identity."

Long story short: if the creature or being in question has two legs and two arms then they likely do not belong in this list. They must not look like us to be included, even if they are ghosts.

Nor do they have to speak like us—or even have a mouth—but thinking at least somewhat like us may be important in a basic ability to understand each other at some level (if required).

No cartoon animals please. The less dragons and beasts behave like us the better. Shapeshifters originally of human form should be excluded. Robots are mostly welcomed, but think more Roomba and less Robbie.

Recommended:
* Iben Krutt's list of Weird Biology: Xenofiction, Speculative Zoology and the Science of Magic
* Stephanie's list of Non-Humanoid Aliens
* Kooshmeister's list of Blob Monsters!
* Andrew's list of Comics and Graphic Novels With Non-Humanoid Protagonists
* Shogo's list for Cosmic and Lovecraftian Horror.