Biomass Mutation

Creatures you control have base power and toughness X/X until end of turn.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Terramorphic Expanse

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

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Nuclear Fallout

Each creature gets twice -X/-X until end of turn. Each player gets X rad counters.

The Wise Mothman

Flying
Whenever The Wise Mothman enters or attacks, each player gets a rad counter.
Whenever one or more nonland cards are milled, put a +1/+1 counter on each of up to X target creatures, where X is the number of nonland cards milled this way.

Contaminated Drink

Draw X cards, then you get half X rad counters, rounded up.

Opulent Palace

This land enters tapped.
{T}: Add {B}, {G}, or {U}.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. This artifact deals 1 damage to you.

Command Tower

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