I wouldn't generally use hand coded WASM in production, but I've used it for educational purposes [1], and just because I'm perhaps a bit perverse [2][3] (3 includes some helper utilities in Common.ts).
It's mostly Rust compiled to wasm binaries. There's also TinyGo and you could use C/C++ as well, but those 3 are a lot less common as far as I can tell.
And Blazor, however I am not a big fan of it, it feels like an escape path for WebForm developers, and I surely don't want to debug that kind of code again, MVC is much better approach.
[1] https://exercism.org/profiles/mikestaas/solutions
[2] https://github.com/mikestaas/wasmfizzbuzz/blob/main/fizzbuzz...
[3] https://github.com/mikestaas/walox/tree/main/src