A few variants I like:

• Weight lifting

I like the progression. It's cool to see the numbers go up

• Cycling

It literally just makes me feel like a kid again, just flying around at quite high speeds. I've recently discovered that this is also a lot of fun to do with friends

• Walking

This is the one that helped me the furthest in weight loss back when I was overweight. You can do basically unlimited amounts of it, and with a podcast or audiobook in your headphones, it doesn't really get boring either.