Thran Portal

The entry condition runs backwards from most fixing you deploy in the mid-to-late game. A shockland lets you pay two life to have it untapped whenever you draw it; a tapland is tapped no matter when you play it. This one keys its untapped state to your board, arriving ready to use only while you control two or fewer other lands. That makes it a smooth early-turn drop and a slow one once your mana has built out, so it wants to hit the board on curve rather than be held for the turn you finally need a color. The tax on its mana abilities is the standing rent: every tap for mana costs an additional life, a bleed that compounds across a long game rather than resolving in a single payment the way a shockland's life cost does. And it fixes narrowly, locking in exactly one basic land type as it enters (a replacement effect resolved before it touches the battlefield, so it arrives already bearing the chosen type), which means one color, not two. The Gate subtype underneath gives it a second identity in decks that count Gates, where the color it taps for matters less than the fact that it counts.