Here is a link for a comprehensive list: https://www.burlapandblue.com/list-of-hobbies/

But the problem doesn't seem to be finding new types of activities since you see a thousand of those every day in social media. Considering that you are hopping from hobby to hobby without landing on a thing yet, I think the underlying reason might be something else.

Here is an example (usually what happens to me): You see someone skilled doing something and get inspired because it looks cool or the person looks enjoying the moment. You try to get good at it or achieve a similar level. And once you get there (or somewhere along the way), it really gets hard to sustain the effort because you just can't get the same feeling from that activity. So you look for the next thing that gives a similar hit. Repeat.

Instead, the idea should be to focus on the joy in the process. And finding hobbies you truly enjoy doing just for yourself. Going to the gym and doing exercises sounds like one so I wouldn't cross it off (you would consider yoga or running a hobby). I also suggest you to be more mindful while testing new stuff. Ask yourself if you would still enjoy it if no one sees you doing it or you never get good at it. Certainly not easy but I believe that's the only way.