While searching for something else, I came across this post on hedonic.ink about font choices for TTRPGs (May 2021). It’s actually a series of four posts, and I haven’t combed through each yet since I’m not pining for a new font at this particular moment, but I wanted to share it so that maybe more people will find it sooner rather than later.
The post talks about what you should be looking for in fonts for your TTRPG books such as licensing, styles, and good combinations for headers and body text (links to fonts and foundries included). It also talks about how those choices should change based on different aspects your overall design, and what should basically always stay the same.
I don’t have much more to add, so I’ll keep this one short and let you head to the hedonic website. Be sure to check out the rest of their site, though it seems to be in transition, and their itch.io market page.