Sauron, the Dark Lord

Ward—Sacrifice a legendary artifact or legendary creature.
Whenever an opponent casts a spell, amass Orcs 1.
Whenever an Army you control deals combat damage to a player, the Ring tempts you.
Whenever the Ring tempts you, you may discard your hand. If you do, draw four cards.

Breena, the Demagogue

Flying
Whenever a player attacks one of your opponents, if that opponent has more life than another of your opponents, that attacking player draws a card and you put two +1/+1 counters on a creature you control.

Vihaan, Goldwaker

Other outlaws you control have vigilance and haste. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)
At the beginning of combat on your turn, you may have Treasures you control become 3/3 Construct Assassin artifact creatures in addition to their other types until end of turn.

Greasefang, Okiba Boss

At the beginning of combat on your turn, return target Vehicle card from your graveyard to the battlefield. It gains haste. Return it to its owner's hand at the beginning of your next end step.

Evelyn, the Covetous

Flash
Whenever Evelyn, the Covetous or another Vampire you control enters, exile the top card of each player's library with a collection counter on it.
Once each turn, you may play a card from exile with a collection counter on it if it was exiled by an ability you controlled, and you may spend mana as though it were mana of any color to cast it.

The Ur-Dragon

Eminence — As long as The Ur-Dragon is in the command zone or on the battlefield, other Dragon spells you cast cost {1} less to cast.
Flying
Whenever one or more Dragons you control attack, draw that many cards, then you may put a permanent card from your hand onto the battlefield.

Ghyrson Starn, Kelermorph

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Three Autostubs — Whenever another source you control deals exactly 1 damage to a permanent or player, Ghyrson Starn, Kelermorph deals 2 damage to that permanent or player.

Shalai and Hallar

Flying, vigilance
Whenever one or more +1/+1 counters are put on a creature you control, Shalai and Hallar deals that much damage to target opponent.

Celestine, the Living Saint

Flying, lifelink
Healing Tears — At the beginning of your end step, return target creature card with mana value X or less from your graveyard to the battlefield, where X is the amount of life you gained this turn.

Orah, Skyclave Hierophant

Lifelink
Whenever Orah, Skyclave Hierophant or another Cleric you control dies, return target Cleric card with lesser mana value from your graveyard to the battlefield.

Henzie "Toolbox" Torre

Each creature spell you cast with mana value 4 or greater has blitz. The blitz cost is equal to its mana cost. (You may choose to cast that spell for its blitz cost. If you do it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)
Blitz costs you pay cost {1} less for each time you've cast your commander from the command zone this game.

Zur, Eternal Schemer

Flying
Enchantment creatures you control have deathtouch, lifelink, and hexproof.
{1}{W}: Target non-Aura enchantment you control becomes a creature in addition to its other types and has base power and base toughness each equal to its mana value.

Cormela, Glamour Thief

Haste
{1}, {T}: Add {U}{B}{R}. Spend this mana only to cast instant and/or sorcery spells.
When Cormela, Glamour Thief dies, return up to one target instant or sorcery card from your graveyard to your hand.

Kaza, Roil Chaser

Flying, haste
{T}: The next instant or sorcery spell you cast this turn costs {X} less to cast, where X is the number of Wizards you control as this ability resolves.

Melek, Reforged Researcher

Melek, Reforged Researcher's power and toughness are each equal to twice the number of instant and sorcery cards in your graveyard.
The first instant or sorcery spell you cast each turn costs {3} less to cast.

Killian, Ink Duelist

Lifelink
Menace (This creature can't be blocked except by two or more creatures.)
Spells you cast that target a creature cost {2} less to cast.

Kambal, Profiteering Mayor

Whenever one or more tokens your opponents control enter, for each of them, create a tapped token that's a copy of it. This ability triggers only once each turn.
Whenever one or more tokens you control enter, each opponent loses 1 life and you gain 1 life.

Indominus Rex, Alpha

As Indominus Rex, Alpha enters, discard any number of creature cards. It enters with a flying counter on it if a card discarded this way has flying. The same is true for first strike, double strike, deathtouch, hexproof, haste, indestructible, lifelink, menace, reach, trample, and vigilance.
When Indominus Rex enters, draw a card for each counter on it.

Optimus Prime, Autobot Leader

Living metal (During your turn, this Vehicle is also a creature.)
Trample
Whenever you attack, bolster 2. The chosen creature gains trample until end of turn. When that creature deals combat damage to a player this turn, convert Optimus Prime.

Optimus Prime, Hero

More Than Meets the Eye {2}{U}{R}{W} (You may cast this card converted for {2}{U}{R}{W}.)
At the beginning of each end step, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)
When Optimus Prime dies, return it to the battlefield converted under its owner's control.

Optimus Prime, Hero // Optimus Prime, Autobot Leader

Raffine, Scheming Seer

Flying, ward {1}
Whenever you attack, target attacking creature connives X, where X is the number of attacking creatures. (Draw X cards, then discard X cards. Put a +1/+1 counter on that creature for each nonland card discarded this way.)