The power to spend two counters from it to essentially draw a card is immense when it costs no additional mana, and the fact that you get +1/+1 counters for lands or spells is the cherry on top, or was it the keyword soup
Auton Solider can enter as a copy of any creature on the battlefield , not just your own
Ratchet, Field Medics convert trigger is anytime you gain life, and when you do you can return an artifact with a converted mana cost less than or equal to the amount of life you gained straight to the battlefield
Millenium Maiden Level 4 LIGHT Illusion / Effect You can only use each of the [1] [2] effects of this cad once per turn
While it was just a Sorcery, it could be combined with lots of other cards for some deadly results
R Rare Labrynth Cooclock X DARK Level 1 [ FiendEffect ] ATK 0 DEF 0 (Quick Effect): You can discard this card