Twitch kind of makes watching something social with its chat feature. Especially if you watch smaller channels, then you can usually even interact with the host, which I think is a lot of fun.
If you like to spend time doing something you feel like helps people, you could go on sites where people post their work like, deviantart, fictionpress, archiveofourown, etc. If you're into any of those things, commenting on everything you like would mean so much to the people that have made whatever you're looking at. Whether that's highlighting your favorite thing about it or giving them constructive criticism.
Omegle can be fun but is really hit or miss. If you've never used it, it pairs you up with a random person to chat with, but oftentimes you can get a complete creeper. Though with their tag feature you can put in any topic to discuss which usually takes care of that. Maybe put in a favorite show that maybe you don't know anyone else who watches, and it tries to match you up with someone else who listed that thing. Just DO NOT use their video chat. Stick to the text chat. I mean there's still creepers in the text chat too, but at least you don't have to actually look at whatever awful thing they have ready in text.
For a long time I ignored reddit because I felt like I hadn't heard anything actually good about it. But if you've spent time on this site and didn't get overwhelmed with the amount of people trying to get mad about literally anything they can think of, then you can definitely handle reddit. When you start finding subreddits you're actually into, you can really find some cool stuff and find conversations to get into about whatever you want. It does take a minute to get into, but once you've found some groups you really like it starts to pick up fast.
If you're an artist, Paintberri has a great community, really cool roleplay groups (which I don't even do but honestly the stories they've been writing are so good I've just been reading them), and an in browser paint tool that I've used think is pretty good.
I realize mst of these are pretty common, but I know in my case most of them I had heard of but waited to use because I'd never actually figured out how they work and what they had to offer, so I thought I'd list and explain them anyway. Hope this helps!