A few days I published a small game built using WASM GC. As far as I know it's among the first. It's a retro vertical scrolling space shooter called Strigoform[0]. It is written in Scheme, the language that Netscape almost put in the browser back in 1995, using the Guile Hoot[1] compiler. If you have the new Chrome it should just work. You can also use Firefox Nightly. Does not work on mobile at the moment as I didn't have time to add a touch control overlay during the game jam, but if you have a Bluetooth keyboard or something you can try though I suspect performance won't be great because I'm just using HTML5 canvas and not WebGL/WebGPU (yet.)
[0] https://davexunit.itch.io/strigoform
[1] https://spritely.institute/hoot/