Most solid colored cats are the result of a recessive gene that suppresses the tabby pattern. The tabby-suppressing gene is not effective on red or cream cats, so you won't see red or cream cats without tabby markings. Solid white cats are the result of a different gene that suppresses color completely. Young white cats often have vague smudges of color on the top of the head where the color is not completely suppressed. Sometimes this persists even in an older white cat.
Smokes are the solid version of silver tabbies.
These cats are very dramatic because when they move, the hair parts and the white undercoat can be seen. Cats with white markings might have larger or smaller areas of white. It might have some white on the face as well. If your cat is randomly patched with different colors, you probably have a tortie, patched tabby, or calico. The patches may be very mingled, or they may be more distinct.