We've got two official WireGuard open source clients coming in the pipeline for Windows and macOS -- one in Rust and another in Go. (Neither are TunSafe, which is C++.)
there are currently at least two actively developped open source userspace implementations in different languages. Two examples are Go and Rust:
https://git.zx2c4.com/wireguard-go/ https://git.zx2c4.com/wireguard-rs/