Material Design is a set of design principles created by Google for developers creating apps for Android. They call it a design language. The concepts don’t apply only to Android, of course. Some of the resources I’ll mention below can be helpful to anyone.
You may be familiar with the way things designed this way look and work, because Google has deployed it on most of its sites since last June.
Material Palette is a bold color picking tool. Simply pick two colors and you are offered a color palette.
Material Palette is quick, simple, and useful to any app developer.
To back up a bit, a definition and description of what Material Design is all about can be found at developer.android.com. It deals with more than color choices. The design concepts also involve animations, shadows, and drawables.
Google also provides a set of basics about Material Design. The Google site discusses the goals and principles of Material Design and goes on to explain style, animation and many more aspects of development using the concepts.
MaterialUp.com offers inspiration in the form of daily examples of how the concepts have been used in websites and apps. This site and Material Palette are interconnected.