Hall of Gemstone

At the beginning of each player's upkeep, that player adds . Until end of turn, they don't lose this mana as steps and phases end.

At the beginning of each player's upkeep, if that player controls more lands than each other player, the player creates a 1/1 green Saproling creature token.

Blue creatures don't untap during their controllers' untap steps.

At the beginning of each player's upkeep, that player may choose any number of tapped blue creatures they control and pay for each creature chosen this way. If the player does, untap those creatures.

If a basic land you control is tapped for mana, it produces mana of a color of your choice instead of any other type.

At the beginning of your upkeep, if you control a blue or black permanent, target creature gets +1/+1 until end of turn. If you control a blue permanent and a black permanent, that creature gets +5/+5 until end of turn instead.

At the beginning of each player's upkeep, that player sacrifices a nonbasic land of their choice.