When starting on a new book project, one of the first things I think of are the typefaces for the interior. How to choose what to use to convey the information to the reader? How heavy should the type look in a character, line, paragraph, and on the page as a whole?
I see four major areas for copy treatment when it comes to roleplaying games: the body copy, the headings, the sidebars, and the tables. Depending on the game, there may be statblocks that need to be detailed, but for the most part a treatment that incorporates the sidebar and table styles are a good starting point for these. I do not consider statblocks as high in the hierarchy of design elements as tables or sidebars are.