Azorius Chancery enters the battlefield tapped. When Azorius Chancery enters the battlefield, return a land you control to its owner's hand. {T}: Add {W}{U}.
Golgari Rot Farm enters the battlefield tapped. When Golgari Rot Farm enters the battlefield, return a land you control to its owner's hand. {T}: Add {B}{G}.
Myriad Landscape enters the battlefield tapped. {T}: Add {C}. {2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.
{T}: Add {C}. {1}, {T}: Add one mana of any color in your commander's color identity. If you spend this mana to cast your commander, it enters the battlefield with a number of additional +1/+1 counters on it equal to the number of times it's been cast from the command zone this game.
Path of Ancestry enters the battlefield tapped. {T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1.