You can create pretty consistent scenarios where you play a room card and unlock the other door: Victor, Valgavoth's Seneschal lets you surveil 2 while your opponents discard a card
Legends and Legendary Lands: Gotta love that the rule card has to state that Legendary Lands are treated as lands instead of creatures
Ich-Tekik, Salvage Splicer Ich-Tekik, Salvage Splicer is much like Slurrk, All-Ingesting, but the Salvage Splicer can be played a bit earlier, golem typal payoffs could mean upside, and putting artifacts into the graveyard often happens far more than creatures going to the graveyard
It has a somewhat-expensive cost at 8 mana, but luckily only has a single red pip which makes it relatively easy to include in most multicolor control and board wipe decks
Charred Foyer // Warped Space Impulse-drawing every turn is nice, although Charred Foyer is a 4-mana do-nothing red enchantment