F# is a great FP language that runs on .NET and there's a growing field of FP proponents working in C#, sort of a Trojan Horse situation trying for a best of both worlds (easy onboarding for C# junior devs, but deep FP options thanks to things like C#'s clever LINQ syntax). LanguageExt is a big part of some of those ecosystems: https://github.com/louthy/language-ext