Material Design Lite (MDL) is a library of components and tools that allow developers to build web pages and applications that conform to the Material Design principles developed at Google. MDL was designed to be lightweight, fast, and easy to use. It provides a range of components such as buttons, text fields, checkboxes, and more, as well as a set of design guidance and a style guide. MDL also offers various tools and services to help developers create a consistent UI experience across different platforms and devices. MDL is open source and can be used for free.
Material Components for the Web is an official successor to Material Design Lite.