If you want to participate, but you don't know what project to work on, fear not!
Here you have a list of project ideas to inspire you and your team
Erlang Code Improver
We have Elvis which will show places where we can improve our code, but it won't fix them. It would be cool to go one step further and build something to apply changes to our code to improve it.
Meck allows you to mock modules and functions. A similar tool that would allow you to mock processes (i.e. step between a registered process and its callers and mock its behavior, passthrough others, count messages received, etc) would be great.
Pick your favorite game and make a server for it, like we did with Serpents. You can make it so the clients can be bots, or they can connect through an API or you can actually provide a visual interface to the game.
We always complain about the cryptic (always right, tho) messages Dialyzer generates. It would be amazing to create something to help newcommers (and experience devs alike) understand them better.