Digital Nomads

It depends if you're looking to meet locals or other travelers/nomads.

If locals, you go to the same activities you would in your home country - rock climbing, social dancing, chess club, knitting circle, volunteer organizations, whatever aligns with your actual interests. For example, I've been to climbing gyms in more than a dozen countries. I always meet people, and sometimes we end up climbing together again, or they extend an invite to join an outdoor trip somewhere.

If you want to meet travelers, though, it's pretty easy: you just sign up for tours - walking tours, day tours, museum tours, etc. Almost every major city in the world has a "free walking tours" available, where you spend a few hours walking the city and tip out your guide - afterwards, it's pretty common to grab lunch or coffee with others from the group you just met. I remember taking day tours out of Bangkok - they drive you to waterfalls, hot springs, an elephant park, etc. and by the end of the day, you've met all the other people on the tour, and you make plans for dinner or some other activity the next day.