Each colour on its own had severe weaknesses, but these could be covered with a deck that contained more than one mana colour
Hurl Through Hell I love a good, clean two-for-one, and I like stealing my opponents threats in Commander
Whenever chaos ensues, creatures you control that are white, blue, and/or black become artifacts in addition to their other types until end of turn
Commander's a different story, but enormous creatures still have a home in multiplayer games
Cloven Casting Cloven Casting might look expensive at 7 mana, but once its on the board, it turns every multicolored instant or sorcery into a double threat
In particular, the Cyclops from The 7th Voyage of Sinbad