Agree with many of the suggestions above, particularly:
Sebastian Crowe's Guide to Drakkenheim
Kobold Press's Deep Magic Books (hopefully with the Theurge and Witch included)
More of Valda's Spire of Secrets - if not the whole book, additional class options (Alchemist, Captain, Craftsman, Investigator, Warden, and Witch), new weapons/weapon masteries (see Mage Hand Press website for their 2024 updates), and spells.
Keith Baker's Eberron books from the DM's guild (or as stated above, at least a player's pack)
Can we get a dr dhrolin's dictionary of dinosaurs? It seems cool
What is your opinion about "Itza's Guide to Dragonbonding" by Draco Studios?
Would love to see the WBN Witch class and their paladin and wizard subclasses
Sebastian Crowe's and the Apothecary Class from Drakkenheim. Easily my favorite 3rd party class. Easily one of the best player options books.
Kobold Press' Deep Magic books
Raider's Guide to Valika
More Heliana and Valda
Ryoko's Guide to Yokai Realms
Fool's Gold: Into the Bellowing Wilds
Humblewood Book 3
Oh, and Keith Baker’s Ebberon books. Even if it’s just a players pack.
Agree with many of the suggestions above, particularly:
Hekna
I feel like we should've had Griffon's Saddlebag Book 1 by now. They said it was "in the works" since they announced Book 2 was coming here
Has anyone threw out Battlezoo from Roll for Combat? Who doesn’t want to play as a monster?