Arcane Signet

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

Command Tower

Inalla, Archmage Ritualist

Eminence — Whenever another nontoken Wizard enters the battlefield under your control, if Inalla, Archmage Ritualist is in the command zone or on the battlefield, you may pay {1}. If you do, create a token that's a copy of that Wizard. The token gains haste. Exile it at the beginning of the next end step.
Tap five untapped Wizards you control: Target player loses 7 life.

Counterspell

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Crumbling Necropolis

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

Bloodline Necromancer

Lifelink
When Bloodline Necromancer enters the battlefield, you may return target Vampire or Wizard creature card from your graveyard to the battlefield.