Google's Material Design guidelines for Android are a living ecosystem that gets continual updates, so it should come as little surprise that Google I/O 2018 brought the announcement of the Material Theme Engine, a developer-facing tool that can help bring apps into compliance with the latest Material Design standards. It comes in the form of a plugin for Sketch, a powerful and multi-faceted app design tool that's popular in the Android world, almost to the point of being the de facto standard for creating simple apps. Essentially, the plugin puts all the tools and assets in place for a developer to build an app according to standard, then lets the developer decide the rest. When applied to existing apps and projects, it can also revamp their assets, though some redesign work will almost certainly be required.
Material Theme Engine brings a large number of assets and animations into Sketch, which a developer can then play around with and remix to their liking. The core conceit of the affair is the fact that developers will be hard-pressed to wander far outside of the bounds of Material Design guidelines while using the plugin. Such a large number of elements are premade and put together just right that all a developer really has to do is paste them together and add in their own unique art, text, sound and programming assets to build out an app. This ensures that developers who don't actively try to deviate from Material Design guidelines will make a compliant app in nearly all cases.
This tool is the culmination of the recently-spotted Material Design 2 that's been making the rounds in the Android news sphere. Material Design 2 was never centered on tweaking what Material Design is or how it behaves, but rather how developers interacted with it. The Material Design Engine is the easiest way for a developer who would otherwise make a bland or non-compliant app to align their vision with the Material Design Guidelines presented by Google. This ensures that their app presents a consistent experience with the rest of the Android or Chrome OS stack and most native apps, keeping users from having a jarring experience and having the added bonus of making beautiful and intuitive app design as easy as possible.