Spectator Seating

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

Terramorphic Expanse

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

This land enters tapped. As it enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Afterlife 2 (When this creature dies, create two 1/1 white and black Spirit creature tokens with flying.)

This land enters tapped. As it enters, choose a color other than green.
{T}: Add {G} or one mana of the chosen color.

This land enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

This land enters tapped. As it enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

This land enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

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

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

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

Whenever you cast an artifact spell, you may pay {1}. If you do, create a 1/1 colorless Myr artifact creature token.