Colorshift

A colorshift is a card that is functionally identical to an old card, with the crucial exception of their color.

These colorshifted cards have the same basic construction of the mana costs of their predecessors, such that, Angelsong from Shards of Alara, for example, whose mana cost is, would be considered a colorshifted version of Lull from Urza's Saga, whose mana cost is and whose effects and card types are the same. Angelsong would not be considered a true colorshift of Lull if its mana cost, for instance, was while Lull's is.

Planar Chaos
The 45 timeshifted cards in Planar Chaos (also known as planeshifted) are all colorshifts.