good job. cant wait to to add these models to my games. or develop new ones. but they are too much poly count more 130?! should reduce polycount
if you are talking about the scene in sketchfab, the grass took all the poly count , lot of duplicate objects can be optimized by instancing geometry in ur engine of choice , can't reduce what is not reduceable (u need polys to make a shape) , it uses only gradient color palette texture , if i used some textures maybe i can reduce it but not it's not the case here,
this is already really low poly if u want lower poly u will maybe need to bake the textures (but not necessary at all , this is already really low poly) and i think u are actually talking about the sketchfab scene(it's the grass and duplicated objects)