Shaun, Father of Synths

Whenever you attack, you may create a tapped and attacking token that's a copy of target attacking legendary creature you control other than Shaun, except it's not legendary and it's a Synth artifact creature in addition to its other types.
When Shaun leaves the battlefield, exile all Synth tokens you control.

Niv-Mizzet, Guildpact

Flying, hexproof from multicolored
Whenever Niv-Mizzet deals combat damage to a player, it deals X damage to any target, target player draws X cards, and you gain X life, where X is the number of different color pairs among permanents you control that are exactly two colors.

Jhoira, Weatherlight Captain

Whenever you cast a historic spell, draw a card. (Artifacts, legendaries, and Sagas are historic.)

Sorin Markov

+2: Sorin Markov deals 2 damage to any target and you gain 2 life.
−3: Target opponent's life total becomes 10.
−7: You control target player during that player's next turn.

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

Faeburrow Elder

Vigilance
This creature gets +1/+1 for each color among permanents you control.
{T}: For each color among permanents you control, add one mana of that color.

Tomik, Wielder of Law

Affinity for planeswalkers (This spell costs {1} less to cast for each planeswalker you control.)
Flying, vigilance
Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, that opponent loses 3 life and you draw a card.

Hostage Taker

When this creature enters, exile another target creature or artifact until this creature leaves the battlefield. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.