Do you like to cook/bake? If so, something I love to do is to try new recipes. Exploring different cuisines from around the world can also be extremely fun. That's not something one needs to do daily, but something like a "Foreign Foods Friday" could be fun. Or if one has never made homemade pizza or other yeast raised edibles, as an example. Giving away excess or inviting others over to enjoy is often appreciated.

Do you have a blog? Or just writing something beyond regular writing can be quite rewarding. I never thought I was good at creative writing (stories, poetry, reflections, etc.) until I pushed myself harder to try. My photo taking skills have also improved over the years.

During good weather months, gardening can be a rewarding pursuit. Or even during cold months, caring for plants or arranging flowers is fun. I took several classes in flower arranging and only then realized how pleasurable that creative activity can be. Any kind of drawing, painting, sculpting, crafting, could be similar.

I agree with the others that volunteering can be rewarding.

If available near you, adult school classes, Meetups, free events/lectures, or college class auditing might appeal to many.