I second The Webster Underground! I know The Webster itself is still open, I drive by nearly daily, so 9 out of 10 The Underground still is as well. (I'll look next time I drive by and edit my comment to lyk.) I dunno if you're familiar with CT, but The Webster is a smaller venue (not best neighborhood unfortunately) that, as a music fan, is phenomenal to see bands at! They've had some big names play there over the years, off hand I'd have to say the best show I've seen there was Jerry Cantrell's (from Alice in Chains) solo tour.

The Underground is next door to The Webster, same building, just smaller than it's already small sibling! That's where a lot of more popular local bands play. I had a friend whose band played shows there quite a bit in the mid to late 2000's. I'm not a performer, so I wouldn't know, but at least he always spoke highly of the venue.

Hope this helps! 🤘