Is this a thread about novels based on RPGs/boardgames, or vice-versa? There's a huge difference between the two.
I initially thought of making it a thread just for novels based in a RPG/boardgame setting, but I thought that might be too restrictive. As well, with some of the larger franchises it gets into a bit of hair splitting. As an example, Dungeons and Dragons for it's 1st decade was only a tabletop RPG, but has since gone on to be the base play mechanics for many video games, has been portrayed in 2 films and an animated TV series and become the setting for 100's of novels. While on the other hand Star Wars was only a trilogy of films and a number of novels for it's 1st decade, but has since been the setting for 2 tabletop RPGs, 3 tabletop miniatures games and a number of board and Card games. A Game of Thrones is another example of a franchise that started out as a series of popular novels, but is now represented in a healthy selection of boardgames and RPG's.