What i really want in books is enough lore and setting to easily make plots. In the book for Myriad song they included 20 planets with quick plot hooks for each. Add to that a good sized monster section with rules to make your own.
Another good book Ninja crusade. They have a few pages of history and one place that includes a list of possible alternate version of important events. Thats really useful as a gm.
Both give me setting and rules to make one shots or campaigns
I support anything that adds splatoon to d&d..
Also tabaxi now reproduce by couching up a hair ball that just keeps growing