Ancient Tomb has been a recent talking point as a ‘replacement’ for Gaea’s Cradle (a land that can produce more than 1 mana). Many players have been finding Tomb to be an interesting inclusion, allowing for turn-2 3CMC players like Ramunap Excavator, Thalia, Heretic Cathar or Tireless Tracker , or even just allowing the ability to play around Daze while staying on curve. Tomb can also allow you to equip faster than most other Stoneforge Mystic decks however with 1-drop mana creatures it doesn’t really change the math.
Neither land does anything for Maverick on turn 1. Cradle of course has the downside of doing nothing with no creatures on board, a reason why most Maverick players tend to side out Cradle against decks like Miracles. Tomb doesn’t have that issue, but in a deck without Aether Vial or Phyrexian Revoker you don’t have any turn 1 plays in Maverick with a start of Ancient Tomb.