Artifact Ramp & Life Gain combo (Modern)

The idea behind this deck is 2-1+2=3. basically, any mana source that taps for 2 or more mana can make extra mana with the Manifold Key or the Voltaic Key. (tap Gilded Lotus for 3 mana, pay 1 to Manifold Key, untapping Lotus, then retap it for a total of 5 mana)

By turn 5 or 6, this deck should be pumping out close to 15 mana. The idea here is you can use Paradox Engine and Well of Lost Dreams to start a virtually infinite loop of playing spells and drawing cards, and playing the cards you drew to draw more cards.

outside of that, you can use Inventor's Fair or Fabricate to tutor up whatever combo piece you find yourself needing. Well of Lost Dreams and Paradox Engine are the most common targets for these spells since they snowball into potentially combing off and winning the game that turn. But. If you find yourself in a sticky situation, or if you just wanna close the game out fast, you can tutor up Blightsteel Colossus and play it the same turn. then you can use Manifold Key to make it unblockable when it attacks.

The only way the deck really defends itself is through lifegain. in the midgame you usually have options that could gain you about 10 life a turn, which helps you float your life total until you can win.

All that being said, one of the most satisfying combos in the deck is Tezzeret, Agent of Bolas + Karn's Bastion. for a total of 9 mana (including B/U) you can play Tezzeret, then proliferate him with the Bastion, and ultimate Tezzeret on the turn you play him. even if this doesn't win you the game instantly (which it often does,) the life total swing is usually too much for an opponent to come back from.