I have experimental stuff for a client written in C++, C#, and I’m tinkering with Nostr in Go now.
Discussion
Not sure what your timelines are, but would you be interested in testing the Aedile C++ project I've been working on? I aim to have event read, event write, and NIP-46 signing finished and unit tested soon, but there's no substitute for real-world testing.
I also want to work on cross-language compatibility; I think I can get the Aedile binaries to work with C#.