Izzet Signet

Crumbling Necropolis

Crumbling Necropolis enters tapped.
{T}: Add {U}, {B}, or {R}.

Accursed Marauder

When Accursed Marauder enters, each player sacrifices a nontoken creature of their choice.

Command Tower

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

Thraximundar

Haste
Whenever Thraximundar attacks, defending player sacrifices a creature of their choice.
Whenever a player sacrifices a creature, you may put a +1/+1 counter on Thraximundar.

Arcane Signet

Rakdos Signet

Nightscape Familiar

Blue spells and red spells you cast cost {1} less to cast.
{1}{B}: Regenerate Nightscape Familiar.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.