Might as well go first :) I've currently been working on the modding system + base mechanics for a platformer game I've been making

The ultimate goal for the modding system is to let people be able to easily add new content to the game. I've separated out data and behaviors so that mods can override variables by just making a text file with the same variable name inside (to easily change things such as movement speed for a character) and they can make a new file in a category to add a new object such as a new character, weapon, etc.

I've got a hot reloading system in place where people can change something in the text files or they can change a sprite and then it gets reflected in game without needing to boot it up again for easily tweaking values while testing

And I've got the ability to easily add some new weapons based on parameters set in the txt files (all of these weapons are made using 1 txt file and 1 script file for each of them (just for basic behaviour changes) and then rest is all generalized into the same weapon framework

images for showing it off https://imgur.com/a/lBdZTwl (imgur is showing an nsfw warning for some reason but its not applicable to this)

edit: I linked one image instead of all of them