Secret Lair has also been used to introduce cards from other brands, reimagining existing cards with new art, names, and flavor to fit the crossover theme
Its a really cool sea creatures deck, but its a lot slower to get going than some of the other options available in blue or Simic decks
If a deck can be built to contain mostly or only cards of that type, then the lands have no restriction other than the deckbuilding constraints
If Costume Closet has left the battlefield or has no +1/+1 counters on it by the time its activated ability resolves, you won't put a +1/+1 counter on the target creature
Want better board sweepers than Find/Finality and Chandra's Ignition
The -2 ability can be great when we are running such a toolbox of interactive creatures, letting us get back a discard, removal, or another casting of Gray Merchant