I had an original Mirrodin block deck (with some cards added from Kamigawa) that was green/artefact, but could potentially play a creature of any colour. The whole point of the deck was to collect together lands that produced obscene amounts of mana to play 'Tooth and Nail' a card that for 7 mana allowed you to either get two creatures from deck into your hand, or put two creatures from your hand into play. For 2 extra mana, you could do both. Creatures in the deck included: 2x Darksteel Colossus (11 mana for an 11/11 indestructible artefact creature with trample that shuffled back into your deck if it went to the graveyard), 2x Sundering Titan (a 7/10 [i think], that destroyed one of each basic land type on entering play, possibly when leaving too), 1x Leonin Abunas (a white creature which made your artefacts untargetable by your opponent), 1x Platinum Angel (an artefact creature that meant you couldn't lose and your opponent couldn't win), 1x Kiki-Jiki the Mirror Breaker (a red goblin legend from Kamigawa, that could make flash-in-the-pan duplicates of other creatures) and a load of Myr Servitors (little 1/1s that bring their dead buddies back to play). Also had Mycosynth Lattice; an artefact that made EVERYTHING A COLOURLESS ARTEFACT.