Grassify is a Blender geometry node setup that adds grass to anything you'd like. It is fully customizable which means you can tweak the grass completely to your own liking and make it work in ANY scene. Next to the grass properties, you can add grass to your own weight paint group or cover everything, have it as still grass or animated grass with customizable wind settings, and even set it to high-quality grass to make each grass strand react to wind individually. The default high-performance grass animates in real-time in Eevee even with very high densities, which means it's highly optimized. The grass is made for both Cycles and Eevee and the results are incredible! The grass shader itself allows you to tweak the dryness of the grass, roughness, and subsurface scattering. 

To see exactly how to use this geometry node setup and to find out what you can customize, feel free to watch my video.

Cheers,
Nino