Command Tower

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

Counterspell

Crumbling Necropolis

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

Arcane Signet

Parnesse, the Subtle Brush

Whenever you or a permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless that player pays 4 life.
Whenever you copy a spell, up to one target opponent may also copy that spell. They may choose new targets for that copy.

Nightscape Familiar

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