A synergy cube, with graveyard matters sprinkled in, with no clear archetypes.

All colors care about graveyards, they can all build a pretty aggressive deck. Obviously certain colors care about things their colors usually care about. Green leans to lands, Red to burn, Blue to non-creatures etc, however they also overlap. For example: Gruul partially cares about discarding lands, Golgari partially cares about sacrificing them and havintg them in the graveyard, Selesnya cares about landfall and simic cares about milling themselves (and milling some lands). This basically applies to other colors too.