Current Languages

    C#: Most widely used CLI language,[1] bearing strong similarities to Java, and some similarity to Object Pascal (Delphi) and C++. Implementations provided by .NET Framework, .NET Core, and Mono.
    C++/CLI: A version of C++ including extensions for using Common Language Runtime (CLR) objects. Provides full support for .NET Framework and library only support for .NET Core. Produces mixed-mode code that produces native code for C++ objects. The compiler is provided by Microsoft.
    ClojureCLR: A port of Clojure to the CLI, part of the Clojure project.[2]
    Cobra: A CLI language with static and dynamic typing, design by contract and built-in unit testing.
    Component Pascal: A CLI-compliant Oberon dialect. It is a strongly typed language in the heritage of Pascal and Modula-2 but with powerful object-oriented extensions.
    Eiffel: Purely object-oriented language, focused on software quality, includes integrated design by contract and multiple inheritance. CLI compliant.
    F#: A multi-paradigm CLI language supporting functional programming and imperative object-oriented programming disciplines. Variant of ML and is largely compatible with OCaml. Implementations provided by .NET Framework, .NET Core, and Mono.
    F* - A dependently typed language based on F#.
    Fantom - a language compiling to .NET and to the JVM
    IronPython: An open-source CLI implementation of Python, built on the Dynamic Language Runtime (DLR).
    IronScheme - a R6RS-compliant Scheme implementation built on the DLR
    Limnor Studio: Is a general-purpose codeless and visual programming system. The aim is to enable users to create computer software without coding in a textual programming language. It can be extended by software developers.
    Nemerle: A multi-paradigm language similar to C#, OCaml and Lisp.
    Oxygene: An Object Pascal-based CLI language.
    PeachPie: A compiler of PHP to .NET and .NET Core. Successor of Phalanger.
    Phalanger: An implementation of PHP with extensions for ASP.NET. Predecessor of PeachPie.
    PowerBuilder: Can target CLI since version 11.1.
    Small Basic: A BASIC-derived programming language created by Microsoft for teaching programming. Supported releases target .NET Framework versions 3.5 and 4.5.
    Silverfrost FTN95: An implementation of Fortran 95.
    Synergy DBL .NET: an object oriented CLI compliant implementation of DBL and DIBOL produced by Synergex.[3]
    Team Developer: SQLWindows Application Language (SAL) since Team Developer 6.0.
    Visual Basic .NET (VB.NET): A redesigned dialect of Visual Basic. Implementations provided by .NET Framework, .NET Core, and Mono.
    Visual COBOL: an enhanced version of COBOL ported to the .NET Framework and to the JVM, produced by Micro Focus.[4]
    PowerShell: An object-oriented command-line shell. PowerShell can dynamically load .NET assemblies that were written in any CLI language. PowerShell itself uses a unique scripting syntax and uses curly-braces, similar to other C-based languages.
    XSharp: X# is an open source development language for Microsoft .NET, based on the xBase language. It comes in different flavours, such as Core, Visual Objects, Vulcan.NET, xBase++, Harbour, Foxpro and more.

Abandoned or deprecated languages

    A#: CLI implementation of Ada.
    Axum: An actor model concurrent programming language.
    Boo: A statically typed CLI language, inspired by Python.
    GrGen.NET - a CLI language for graph rewriting
    IronRuby: An open-source CLI implementation of Ruby, built on the Dynamic Language Runtime (DLR).
    J#: A CLI-compliant implementation of Java. The compiler is provided by Microsoft. J# has been discontinued. The last version shipped with Visual Studio 2005, and was supported until 2015.
    JScript .NET: A CLI implementation of ECMAScript version 3, compatible with JScript. Contains extensions for static typing. Deprecated in favor of Managed JScript.
    Managed JScript: A CLI implementation of JScript built on the Dynamic Language Runtime (DLR). Conforms to ECMAScript version 3.
    Managed Extensions for C++: A version of C++ targeting the Common Language Runtime (CLR). Deprecated in favor of C++/CLI.
    Niecza - A CLI implementation of Perl 6.

Related

    IKVM.NET: A Java virtual machine that can be used to run Java and other JVM languages (e.g., JVM like Groovy, Scala) upon CLI implementations.