Arid Mesa

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Sundown Pass

This land enters tapped unless you control two or more other lands.
{T}: Add {R} or {W}.

({T}: Add {R} or {W}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

{T}: Add {C}.
{T}: Add {R} or {W}. This land deals 1 damage to you.

{T}: Add {C}.
{R/W}, {T}: Add {R}{R}, {R}{W}, or {W}{W}.

This land enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

This land enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

This land enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {W}.

As this land enters, you may reveal a Mountain or Plains card from your hand. If you don't, this land enters tapped.
{T}: Add {R} or {W}.