One of the very first things I thought of when I heard about WASM is, "Oh.. It would be so fun to build FORTH on that". I never got around to it (yet) and from a quick search, there are already a ton of implementations. But I think this is one of the things about FORTH: it's not just that you can run it on the metal. It's that you can easily build a FORTH environment for pretty much any metal you can think of. Bootstrapping from absolutely nothing to a very productive environment is really an empowering feeling. I always thought it was a shame that there are so many people who have made a Lisp, but so few that have made a FORTH. I kind of feel like both of these tasks should be required material in school... Though I only have nebulous feelings about why it is valuable... Not sure I could explain it to someone who hasn't done it already.
I haven't done any serious Forth programming in 30+ years, but every time I see a limited resources programming environment, I immediately get the urge to implement Forth on it. "This new game is going to include a DCPU-16 virtual computer you have to program? Great, all I need to do is implement Forth on it..."
Luckily for my already very limited spare time, so far I've managed to resist this urge.