I will repeat what a few have said, but my take is to try things you have never done before. Some might be:
Pinhole photography
Toy camera work - this could include Diana/Holga type cameras
Macro photography
Astrophotography
Lumen prints
You didn't say if you have a darkroom, but I find much inspiration in mine. Try some other processes like:
Toning - there's a lot that can be done here.
Liquid Light on various papers or objects.
Lith printing
Sabbatier effect prints
I find it great to use a large format camera technique, even with a smaller camera. I like my Mamiya Super. I set it up on a tripod and really contemplate my picture. I make make only three or four exposures in an afternoon, but each one is the result of a lot of thought (not that they're all good!). I think just snapping a lot of photos becomes boring.
A final thing is, what do you do with your photos? I find a lot of enjoyment in selling mine. It means somebody else likes them too. I mount, matt and frame photos for display, and put them in art shows and galleries. I don't sell a lot but each sale is rewarding. Also, seeing a dozen or more of your photos up on a gallery wall lets you know what kind of work you are doing. I always see something wrong with a photo that I thought was good. Leads me to improve.
Just MHO.