sandspiel is quite popular and is built using WASM: https://sandspiel.club/
Google Earth - https://blog.chromium.org/2019/06/webassembly-brings-google-...
Ruffle (the "make Flash run safely" tool) - https://ruffle.rs/
Ableton's Learning Synths - https://learningsynths.ableton.com/
etc etc. It's just hard to tell when something is using WASM when it "just works" and is indistinguishable from optimized JavaScript
(cough also my WIP game is being built in WASM.Rust, https://ant.care/ https://github.com/MeoMix/symbiants I've been enjoying the experience!)