Photoshop does not have a way to make a multicolored brush (artists have been complaining about that for years, by the way). But from the looks of what you're doing, it's a pretty simple dot with a stroke. A round brush with 100% hardness is all you need. Make a different layer for each style you want (looks like that's simply color at the moment), place all of the dots, then use the layer effects to make the stroke and/or fill style. For flexibility, you might start with a 50% gray dot, then the color overlay effect, or a hue/saturation adjustment layer can be used to dial in the exact color you desire.