Depends very much on what you enjoy. My interests are in wildlife, so I've found myself an organisation which values my skills. I do lots of plant, fungus and animal surveys, explore new places, learn about new groups, and feel valued for my expertise. Free training in first aid, winch operating, dry stone walling, using a scythe etc.
In another hobby I helped organise a national conference for several years, got to meet lots of people, and felt involved in it in a way that you don’t as a mere participant.
There’s masses of community service type opportunities - JP, prison visitor, school governor, patients’ representatives for GPs, hospitals, Civic Societies, CPRE.
I’d say that anything you enjoy doing, you get a lot more out of it if you get involved in the organisation, better opportunities, steer it the way you want it to go. The key is to do jobs you enjoy and say no to things you don’t fancy (that’s the perk of being a volunteer). I always avoid things that need a regular commitment from me, I like to control my own time. If I organise a fungus foray, it’s a place I want to visit,on a day that suits me, and doesn’t start at silly o’clock in the morning