Org-d20 is a minor mode for Emacs’ Org-mode for GMs running games whose rules centre around rolling d20s. It should be useful for Dungeons and Dragons 3rd, 4th and 5th editions, Paizo’s Pathfinder, and d20 System games like d20 Modern.

The idea is that you’re already keeping your campaign notes in an Org-mode file. This minor mode does useful things for you while you are visiting that buffer. For example,

- rolling dice, with 5e’s advantage and disadvantage displayed in case those are needed; - tracking combat turns and rounds right next to your existing description of the monsters and the terrain.