The best card to be on the lookout for would be Skullclamp
In casual play, its simply a card you own thats not in your starting deck
Zirda, the Dawnwaker can help reduce your cycling costs, too
Creature - Dragon Color tag templates(None) Gwenom, Remorseless Deathtouch, lifelink Whenever Gwenom attacks, until end of turn, you may look at the top card of your library any time and you may play cards from the top of your library
For example, if Bottomless Pool // Locker Room is on the battlefield with both doors unlocked, its names are Bottomless Pool and Locker Room, its mana value is 6, it's a Room Enchantment, and it has the abilities in each door's text box
Frequently, Cavern of Souls shows up in tribal decks, such as Humans, Spirits, and Elementals, but that hasnt stopped Amulet Titan and other decks from playing it to force through specific high-value creatures