Selected programs, that are already ported to Webassembly:
busybox ... in Busytex
bzip2
coreutils (subset) ... in Cowasm; in Wasmer
dash shell (with issues) ... in Cowasm; and also in a branch of Wasmer
libreoffice
libedit
libffi
openssl
python ... PEP 11 lists what platforms are supported by CPython in some official fashion ... In the case of WebAssembly, there are two triples at the tier 3 level: wasm32-unknown-emscripten, wasm32-unknown-wasi
sqlite
tar
vim
Links to mini systems, that work in browser, are being collected at r/browserPOSIX
the state at the end of 2022
https://www.reddit.com/r/linux/comments/ztxa6a/porting_of_linux_programs_to_webassembly_the/
Selected programs, that are already ported to Webassembly:
Links to mini systems, that work in browser, are being collected at r/browserPOSIX