These were inspired by my colleagues in my College Essay Forum for Counselors private Facebook group:
Taking care of younger siblings
involvement in your church/temple/mosque, etc.
photography
songs
creating your own music/beats
cleaning houses
helping the elderly with groceries
reading to the elderly
crafting (bracelets, arts, painting, beads, etc.)
taking a part-time job to help with family expenses
being the go-to tech person or social media expert for a family, neighborhood, organization, and/or school
starting and running own small businesses (lawn mowing, tutoring, power washing, baked goods, children's party planner)
writing
playing instruments
ventriloquism
self-taught language courses like Duolingo
taking MOOCs to learn coding
composing EDM
selling stuff on eBay
arts & crafts
fashion blogging
beekeeping
glass-blowing
scuba diving certification
EMT certification
academic enrichment (summer program, online class certificate, etc.)
training pet goats, dogs, parrots to become therapy animals and getting them certified to visit senior living facilities
cleaning out grandma's attic stuff collected over the years, selling it on eBay, then saving that money to buy a car
maintenance or set-up for high school sporting events (baseball field prep, setting up the timing equipment for swim meets or track meets)
juggling or unicycling
yoga
mountain-biking
bird watching
sport refereeing (not in their primary sport)
Book Club (outside of school)
cosplay + designing costumes
Fantasy football statistician, manager, recruiter, webmaster
listing all the books you've ever read
Got an activity that's not here but should be? Add it in the comments below!