I will edit this with details later. For now I just wanted to conjecture. A skin pack for the whole game (every unit), which makes all units types of bacteria, would be cool. I just thought so because you play like a spreading plague so literally looking like an infectious disease spreading would be cool. Also, models easy makeable and easy to read from distance and prob easy to icon for. discuss.
Pollen? It could look like pollen. Actually, in retrospect, if you were to make icons, based on the shapes of bacteria, based off the terrain of the unit, you would actually have some pretty readable icons, I might make icons early for this just to see how.