JiuJitsu has been a great place to make friends. On open mat days you spar with someone for ~5 minutes then chat a bit, then find someone else and repeat. Small group chats at the end, maybe grab some food.

The are a lot of IT oriented people at my gym, but also surgeons, lawyers, business owners, etc...

The key, like anything, is try a few different schools to find the vibe you want.