I was unaware my mod had been dissolved - I made no such announcement and generally I am available in the undertow discord and other discord servers. I've been semi-active and hadn't released my not-yet ready code as landon had updated my mod for me.
I at least released a version with what I have at the moment.
Back on track though - I would just try to experiment at first, read random classes in the code, play the game and see what you feel could be changed or cool to try out / edit.
If you create a change you consider cool - its possible to ask the devs to implement it into the base game which you could ask how later.
I suppose what I'm trying to say is just play around and have fun learning how to edit the game and where things in Barotrauma code are at
Some examples of what modders added in the past: Crowbars, throwing medical drugs, multi-traitor, new CPR mechanics + animation.
If your completely out of ideas, its possible barotraumas github feature requests could have something - but honestly I'd just play with the code and see if you get any suggestions from players here or in the undertow games discord if you ask there.https://github.com/Regalis11/Barotrauma ... %20request
(Feel free to search without the tag too)