M#

M# is a high-level, statically-typed programming language that combines the object-oriented and functional programming paradigms. It is primarily used for developing cross-platform applications and services within the .NET ecosystem.

Popularity: Less than 1% of developers are using or have used this language.*
*According to StackOverflow's 2023 survey.

Repositories on GitHub: 2,681

• Official Website
• Wikipedia page