Tabby
Technically a pattern, not a colour, and the tabby community will correct you on this at length. The one constant is the "M" marked across the forehead. Past that: mackerel (thin parallel stripes), classic (swirled, marble-like blotches), spotted, or ticked, each with strong opinions about the others.
Spotted in the wild
The most common coat pattern in the world, which the tabby itself will insist is proof of quality, not just genetics doing the statistically obvious thing.