Lfortran

It is a flexible and expressive dialect of Java, which compiles into readable Java 8 compatible source code. You can use any existing Java library seamlessly. The compiled output is readable and pretty-printed, and tends to run as fast as the equivalent handwritten Java code.

It is the open, royalty-free standard for cross-platform, parallel programming of diverse processors found in personal computers, servers, mobile devices and embedded platforms. It greatly improves the speed and responsiveness of a wide spectrum of applications in numerous market categories including gaming and entertainment titles, scientific and medical software, professional creative tools, vision processing, and neural network training and inferencing.

PostSharp enables developers to eradicate boilerplate by offloading repetitive work from humans to machines using aspects: special kinds of custom attributes that modify the behavior of code they are applied to.

Helix allows you to write Ruby classes in Rust without having to write the glue code yourself.

It is the Clojure(Script) IDE that understands your code. Advanced structural editing, refactorings, VCS integration and much more, all out of the box.

Collections of libraries built to make it easier to use Azure services from your language of choice. These libraries are designed to be consistent, approachable, diagnosable, dependable, and idiomatic.

It is a PowerPoint manipulation library that allows developers to create, modify and convert presentations in .NET applications.

It is an extension library for Google Guice that provides many useful features. It introduces new annotations for classpath scanning, lifecycle management, and more.

Native Ruby extensions in Rust

It is a plug-in system for everyone. It is designed to be flexible, fitting into codebases of all shapes and sizes, but opinionated enough so that things just work the way they should.

It is the collection of libraries that are needed by ported applications to support features that are not available, or are too different, in the standard .NET Framework.