Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Plains

Prairie Stream

({T}: Add {W} or {U}.)
This land enters tapped unless you control two or more basic lands.

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Ghost-Spider

Flying, vigilance, haste
Whenever you play a land from exile or cast a spell from exile, put a +1/+1 counter on Ghost-Spider.
Remove two counters from Ghost-Spider: Exile the top card of your library. You may play that card this turn.

Gwen Stacy

When Gwen Stacy enters, exile the top card of your library. You may play that card for as long as you control this creature.
{2}{U}{R}{W}: Transform Gwen Stacy. Activate only as a sorcery.