Possibly the best-known swords in Magic are the Mirran swords, though Id bet a lot of Commander players have seen Sword of the Animist quite often
Continue this loop to life drain your opponent
Before your turn comes back around, crack the Polluted Delta that you played from an earlier turn to shuffle away Armaggon as you realize it's only turn four
The combo is either seven mana in one go or four then five with none to spare
For example, if an opponent controls Blood Moon, an enchantment which says "Nonbasic lands are Mountains," and you play Rootpath Purifier, Blood Moon can no longer apply to the lands you control because they are all basic
They can be flashed back with Snapcaster Mage or Lier, Disciple of the Drowned, or returned to your hand via Archaeomancer