Sejiri Steppe

The protection grant is the entire reason this land exists: a defensive trick folded into a land drop, with the white source as an afterthought. What elevates it above a slow tapland is that the trigger fires whenever the land enters, not only on a normal land-for-turn play. Drop it for the turn and it doubles as offense: name a blocker's color to push a creature through, or name the color of an anticipated kill spell to pre-empt the removal you expect on the swing-back, and the protected creature carries that grant through your own combat step. The deeper line is to put it onto the battlefield at instant speed: Knight of the Reliquary fetches it tapped in response to a removal spell, mid-combat, or to blank a damage source, and the enters-tapped clause stops mattering because the protection was always the point. That fetch line costs nothing but a tap and a sacrificed land, turning a permanent you would have played anyway into a free protection effect that adds back to your manabase as it resolves. Choosing the color at resolution is what keeps it flexible, since protection covers damage, enchanting, blocking, and targeting: the same land fizzles a chump block one game and turns aside a targeted destroy spell the next. It will not save a creature from a global wrath, since destroy- and exile-based sweepers ignore protection entirely, but against pointed removal and combat math it hides inside the manabase as just another white source.