Rust: Which everyone seems to know about and I'm sure lots of people will be able to explain why.

So I'll focus on ... Haxe: Which is known in a few circles, but If I talk to a random person about it they've never heard of it.

Haxe is a garbage collected strictly typed compiled language with type inference. It compiles to a variety of platforms including C++, Javascript, Flash Bytecode, Neko VM bytecode, even PHP. More recently it has been growing support for C#, java, python and lua.

It's just a nice language to use. A combination of the cool features like pattern matching case statements, and the simple tidiness of the basics.

    for (minion in party) {
      minion.jumpToTheLeft();
    }

Just little things like not having 'for (var minion in party)'. It clears the clutter. while still protecting you.

In many respects, when compiling to JavaScript, it serves the niche that Dart and Typescript aim at. I think the fact that it is independent should not be underestimated. Google people tend to use Dart, Microsoft people use TypeScript. Haxe is not on a 'side' people use it because of what it is, not who made it. I'm rather against provenance as a reason to use a language.

The best way to get a good feel for Haxe is to go to http://try.haxe.org and look-at/run some of the examples.