Is there a DevRant trello board or something for roadmap and making feature requests?

There's no public board/roadmap right now. The best way to submit a feature idea is through the in-app feedback form.

The next immediate feature is @mentions in comments which should arrive early next week. After that we'll finish up the basic web version of the app (which is pretty close to being done). Beyond that, we're open to ideas!

A few people have suggested a "topic of the week" where we can run some contest around a specific type of rant, which we also want to do something with :)