For the purposes of this list Ill be looking at base versions of cards, so no alt-arts or special treatments in the main list (Ill touch on them at the end, though)
like the GW lifegain deck, the UR deck uses these triggers as fuel for a potent tempo-aggro engine
$0.59 Grim Guardian Journey into Nyx $0.59 Extinguish All Hope Commander Masters $0.99 Redress Fate Duskmourn: House of Horror Commander Decks $0.79 Fear of Sleep Paralysis Duskmourn: House of Horror Commander Decks $1.79 Summon: Primal Odin Final Fantasy $3.99 Kaya's Ghostform War of the Spark $6.49 Sphere of Safety Return to Ravnica $17.99 Ondu Spiritdancer Duskmourn: House of Horror Commander Decks $2.49 Summon: Yojimbo Final Fantasy Commander Decks $0.39 Ashiok's Reaper Wilds of Eldraine $0.35 Inquisitive Glimmer Duskmourn: House of Horror $2.99 Secret Arcade // Dusty Parlor Duskmourn: House of Horror Commander Decks 0 results found
Theres practically no reason not to run Sol Ring in a deck, especially when you can play a Sol Ring on your first turn, and follow it up immediately with a two-mana mana rock like Arcane Signet or a Thought Vessel
(6/22/2015) If Gideon becomes a creature due to his third ability, that doesn't count as having a creature enter the battlefield
Enigma Sphinx This gets a higher ranking than Ethersworn Sphinx because its still a respectable combination of stats and value, cascade scales well with higher mana value cards, and Enigma Sphinx can reset itself when it dies