I'm aware of 4 now. Here are the other 3:

Bolt: a language with in-built data-race freedom! (recent discussion: https://news.ycombinator.com/item?id=23122973) - https://github.com/mukul-rathi/bolt

Bolt: A programming language for rapid application development - https://github.com/boltlang/Bolt

BOLT: a programming language that was desinged for begining programmers who have never seen code before in their life - https://sourceforge.net/projects/boltprogramming/files

I'm very much in favor of authors choosing unique names for programming languages because there's still plenty of good names up for grabs without having to step on someone's toes. If the project is dead, that's one thing; the data-race one was a research project and hasn't had any activity in 5 years. BOLT last modified in 2014.

But beariish/bolt and boltlang/bolt were started in the same year and are still under active development. With boltlang/bolt obviously snagging the namespace first, I think they should have claim to the name for now. That said, neither seems to have registered any domains, so whoever gets bolt-lang.org/com/net first will probably have an easier time defending a claim.

Not to mention the facebook after compilation optimizer called bolt.