On augmentation I haven’t gone beyond the things you described. I tried to think of the universe of possible images for this kind of problem and, probably same as you did, things like Crop don’t seem to be the best approach.
I haven’t been working with changing the colors of the images yet (say RandomContrast, RandomBrightness. Do you think they add to the model generalization? Couldn’t it be that the channels (i.e. colors) add information for the model? (took the title for the thread very seriously here though lol)