At Tor.com Armstrong tagged five SFF books with dogs (and dog-adjacent individuals) as key characters," including:
Dol in the Villians Duology by V. E. SchwabRead about the other entries on the list.
Many people, including myself, don’t enjoy reading anything where a dog dies. Dol is a unique exception to this rule—because although he does die (more than once, actually) in V. E. Schwab’s grippingly dark duology about two best-friends-turned-enemies with supernatural powers, he is brought back to life by his loving owner, a young girl named Sydney who can bring once-living things back from the dead. Dol, despite dying multiple times, is the closest on this list to being a regular pup—he’s just a big old black dog with floppy ears who loves his owner Sydney. He is a great friend, and keeps her company while her world is threatened by the supernatural machinations going on around her.
--Marshal Zeringue