I've made a somewhat particle effects that throws about 50 sprites. I wanted each of them having a random brightness between 80 and 100.
Because the brigthness shader was too slow, I instead made 5 frames of the same sprite which I changed its colors to have a similar effect to 80, 90, 100, 110, 120 brightness.
When a sprite spawns, it uses a random frame between these.
It works well. I liked the layer idea and I thought about using it, but I don't really want to have about 5 layers only for this.