> If your tabletop roleplaying game has an "orc" species and "rogue" class and "sword" equipment, is WotC going to sue you?
There are plenty of games that already have those. In fact, there's an entire sub-genre of D&D-like game ("OSR") designed around directly emulating older editions of D&D, based on the fact that you can't copyright game mechanics themselves, just the text that expresses them.