Horses can have a great variety of white patterns. All of the following white patterns can occur on any color horse, with any combination of dilutions, modifiers, and other white patterns. For example, it is completely possible to have a tobiano/sabino/splash/roan/palomino. However, while it is possible, not all horse breeds carry all white patterns and dilutions, and possible does not equate to a likely outcome. All white patterns can also be present in minimal and maximal forms. Minimal can be very minimal indeed (think white spot on the bottom of a hoof for frame), and maximum expression can be almost completely white, especially when more than one pattern is present.
Photo Submitted by Emily West Homozygous Tobiano Stallion with Frame Homozygous for Black as Well