Coin collecting/numismatics.

I can't speak for other collectors but my focus is on ancient coins, mostly Roman imperials.

The amount of history and artistry in those coins is off the charts amazing, and every single one is like a tiny window into the past. To many outsiders it seems like one of the stuffiest things to do. It does require a good bit of research which can get a bit dry at times, but nothing beats that feeling of holding literal treasure of 2000+ years old.

Gardening. There are a million things to learn, and every year is an adventure.

Also making things from yarn. So many different techniques, yarns, styles, and colors. And if you have a project that is easy, you can binge watch at the same time.

Plastic scale modelling.

Trust me, it gets deep and expensive. The almost irresistible desire to increase the size of one's "stash" by buying models you'll never get around to building. The need to have the exact shade of paint used on a 1942 tropical BF109. The need for at least 3 airbrushes. The obsession with the tools.

HELP!

But it's really quite enjoyable and once you accept that if what you've built gives you pleasure and that you're happy with it, you've got it beat.