Bluegrass instrumental musician
Shape note singer (folk music)
Folk music arranger (sheet music)
Festival performer/workshop instructor
Those former hobbies/now avocations allow me to travel and get hired performing and teaching workshops around the US doing these activities...to me they're like paid vacations. I also used to and still go to local jam sessions every week and singings when they occur here in Texas and a few out of state.
Whatever you decide to do for a hobby or hobbies, it sure doesn't hurt to take up something that you might could earn a little $$$ on the side while working as well as do more of it for extra income when you do finally retire.