F# is a strongly-typed, functional language that is part of Microsoft's .NET language stack.
Although F# is great for data science problems, it can elegantly handle almost every problem you throw at it.
As F# runs on the .NET runtime, you get access to the entire .NET ecosystem, including all packages on nuget.org.
Integration with existing .NET code is further simplified due to F# also allowing you to write object-oriented code.
The home page for F# is fsharp.org and a great introduction to F# can be found at the F# for fun and profit website.