Three wildcard files, one with simple colors, one with more creative colors, and one with color palettes that make some very pretty images.
I suggest playing around with the color palette file. It causes different effects depending on how you incorporate it into your prompt. Putting "color palette" before the wildcard adds some interesting effects depending on the checkpoint you are using. Weighting the wildcard increases the effect of the wildcard and makes it even more awesome. Grouping it together with a specific object keeps the effect more localized. Really just play with it and see what you get.
I'd love to see any images generated with this!