Homebrew

(Tabletop Roleplaying Games:)
A piece of content produced by a third party for a tabletop roleplaying game (like D&D), typically a dungeon master or someone who wants to try and slip some broken shit past their dungeon master so they can be a shiteating munchkin.

Player: "Hey DM, check out this homebrew I found on Reddit."
Dungeon Master: "Yeah, no."

"The DM uses a lot of cool homebrew stuff. The game is pretty fun."