Michiko Konda, Truth Seeker

Whenever a source an opponent controls deals damage to you, that player sacrifices a permanent of their choice.

Urza's Incubator

As Urza's Incubator enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Loran of the Third Path

Vigilance
When Loran of the Third Path enters, destroy up to one target artifact or enchantment.
{T}: You and target opponent each draw a card.

Denry Klin, Editor in Chief

Denry Klin, Editor in Chief enters with your choice of a +1/+1, first strike, or vigilance counter on it.
Whenever a nontoken creature you control enters, if Denry has counters on it, put the same number of each kind of counter on that creature.

Beacon of Immortality

Double target player's life total. Shuffle Beacon of Immortality into its owner's library.

Plains

Kongming, "Sleeping Dragon"

Celestial Regulator

Flying
When Celestial Regulator enters, choose target creature you don't control and tap it. If you control a creature with a counter on it, the chosen creature doesn't untap during its controller's next untap step.

Masako the Humorless

Flash
Tapped creatures you control can block as though they were untapped.

Sol Ring

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.