I think some kind of a list of tools and probably templates, libraries etc. could help people decide to participate. I am not a big fan of GameMaker, quite the opposite. But they do provide a topic in their forums for the "GMC" jam. I don't want to link there because it's GameMaker-centric by its nature.
Let me start with a link to a thread in the official Monogame forums:
I have no idea what "U-MG-RL" stands for. It's a list with a lot of tutorials and other stuff so people can get acquainted or just get started with Monogame.