This download contains 10 plant objects.
These are simple models, not really optimized – still they might be useful to mix into other plant populations. The files are available in following formats: *.obj, *.vob, *.tgo, *.c4d, vray for *.c4d, *.blend.
This tutorial will show you several approaches to create a convincing clump of grass. Cinema4D, Xfrog 3.5 and Xfrog 4 were my applications of choice, but you should be able to follow along with other 3D software too.