This land enters tapped. {T}: Add {W} or {B}. {1}{W}{B}: This land becomes a 2/3 white and black Elemental creature with lifelink until end of turn. It's still a land.
This land enters tapped. {T}: Add {G} or {W}. {1}{G}{W}: Until end of turn, this land becomes a 3/4 green and white Elemental creature with reach. It's still a land.
This land enters tapped. As it enters, choose a color. {T}: Add one mana of the chosen color. {T}: Add two mana of the chosen color. Spend this mana only to activate abilities of land sources.
This land enters tapped. {T}: Add {U} or {R}. {2}{U}{R}: Until end of turn, this land becomes a 1/4 blue and red Elemental creature with "{0}: Switch this creature's power and toughness until end of turn." It's still a land.
This land enters with a charge counter on it. {T}: Add {C}. {X}{X}, {T}: Put X charge counters on this land. {3}, {T}, Sacrifice this land: Destroy each nonland permanent with mana value equal to the number of charge counters on this land.
{T}: Add {C}. {1}: This land becomes a 1/1 Blinkmoth artifact creature with flying until end of turn. It's still a land. {1}, {T}: Target Blinkmoth creature gets +1/+1 until end of turn.
This land enters tapped. {T}: Add {W} or {U}. {3}{W}{U}: Until end of turn, this land becomes a 4/4 white and blue Elemental creature with flying and vigilance. It's still a land.
Whenever a creature deals combat damage to you, that creature's controller gains control of this land. {T}: Add {C}. {1}, {T}: Attacking creatures get +1/+0 until end of turn.
This land enters tapped. {T}: Add {U} or {B}. {1}{U}{B}: This land becomes a 3/2 blue and black Elemental creature until end of turn and can't be blocked this turn. It's still a land.
{T}: Add {C}. {2}, {T}: Exile target creature you control. {4}, {T}, Sacrifice this land: Return each creature card exiled with this land to the battlefield under its owner's control.