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.
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.
Colorless Eldrazi spells you cast cost {2} less to cast. {7}, {T}: Search your library for a colorless creature card, reveal it, put it into your hand, then shuffle.
This land enters tapped. {T}: Add {B} or {R}. {1}{B}{R}: Until end of turn, this land becomes a 2/2 black and red Elemental creature with "{X}: This creature gets +X/+0 until end of turn." It's still a land.
This land enters tapped. {T}: Add {R} or {G}. {2}{R}{G}: Until end of turn, this land becomes a 3/3 red and green Elemental creature with "Whenever this creature attacks, put a +1/+1 counter on it." It's still a land.
This land enters tapped. When this land enters, target creature you control gains protection from the color of your choice until end of turn. {T}: Add {W}.
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.