From what I've seen, Rails and Node tend to be the big contenders, with quite a few people starting to move things to Go now. That's just anecdotal though, hard to get much concrete numbers on this sort of thing.

https://remoteok.io aggregates remote jobs, and has lots of them tagged by language, which might be a route to try and get more substantial answers to this.

Let me know if you/anybody has a go at this actually, I might have a go myself next week, if nobody else has in the meantime.