Arcane Signet

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

Sensei's Divining Top

{1}: Look at the top three cards of your library, then put them back in any order.
{T}: Draw a card, then put this artifact on top of its owner's library.

Dimir Signet

Gather Specimens

If a creature would enter the battlefield under an opponent's control this turn, it enters under your control instead.

Sol Ring

Sen Triplets

At the beginning of your upkeep, choose target opponent. This turn, that player can't cast spells or activate abilities and plays with their hand revealed. You may play lands and cast spells from that player's hand this turn.

Orzhov Signet

Telepathy

Your opponents play with their hands revealed.

Counterspell

Azorius Signet

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice this artifact: Draw a card.

Stormscape Familiar

Flying
White spells and black spells you cast cost {1} less to cast.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.