Human

From Magic: The Gathering

Humans are one of the most controversial creature types in Magic. Obviously, we all should know what a human is, but that's exactly why some people had a problem with them being introduced to Magic. Many felt that, because Magic is a fantasy game, and therefore escapist, humans should simply not be a part of it. However, humans do exist in other instances of fantasy lore, such as Dungeons & Dragons and Lord of the Rings. Furthermore, Magic had adopted a race-class typing system (such as goblin shaman, cephalid wizard) and already printed many "human" cards since the game's creation. To leave humans out of the system would be unfair, so humans were dragged onto the scene.

Humans have no mechanical ties, and yet they still have some unique traits. For one, though they are a majorly supported creature type, there are no cards that explicitly help or care about humans. Some humans will help other creature types heavily populated by humans (such as soldier or barbarian), but no card specifically affects other humans. It is also relevant to note that both tribal blocks, Onslaught block and Lorwyn block, kept humans out of tribal support (and Lorwyn totally excluded humans from the entire block).
Humans are also readily included in all colors for all roles. They are essentially the hole-filler creatures who can be anything, but are generally one-man armies.