Warlord

Warlord is a slang term used by Magic R&D to describe creatures the following ability: "This creature's power and toughness is equal to the number of creatures you control."

This ability started in red with Keldon Warlord in Alpha. R&D later moved it into green, as green is the creature color. The ability then got moved into white because white is the army color that likes giving rewards for having lots of little creatures. The ability is still done a little in green, but it's primary in white these days. The ability also dropped from Rare to Common for the vanilla version, though the ability overall tends to be supplemented with another to push it to uncommon.

Examples
Voice of Resurgence creates an Elemental token with warlord.