This video features how to build the main components of a medieval castle. The cool thing about this is you can incorporate other modular structures such as castle walls, battlements, and other components associated with a castle. This modular structure would be a great fit for Dungeons and Dragons or any tabletop game.
3D files:
Drawbridge... https://www.thingiverse.com/thing: 4151733
Dungeon door and gate... https://www.thingiverse.com/thing: 3335939