Cruel Ultimatum

Target opponent sacrifices a creature, discards three cards, then loses 5 life. You return a creature card from your graveyard to your hand, draw three cards, then gain 5 life.

Triskaidekaphile

You have no maximum hand size.
At the beginning of your upkeep, if you have exactly thirteen cards in your hand, you win the game.
{3}{U}: Draw a card.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Othelm, Sigardian Outcast

{2}, {T}: Choose target creature card in your graveyard that was put there from the battlefield this turn. Return it to the battlefield tapped.
Friends forever (You can have two commanders if both have friends forever.)

Titanic Ultimatum

Until end of turn, creatures you control get +5/+5 and gain first strike, trample, and lifelink.

Brilliant Ultimatum

Exile the top five cards of your library. An opponent separates those cards into two piles. You may play lands and cast spells from one of those piles. If you cast a spell this way, you cast it without paying its mana cost.

Inspired Ultimatum

Target player gains 5 life, Inspired Ultimatum deals 5 damage to any target, then you draw five cards.

Spirited Companion

When Spirited Companion enters, draw a card.

Emergent Ultimatum

Search your library for up to three monocolored cards with different names and exile them. An opponent chooses one of those cards. Shuffle that card into your library. You may cast the other cards without paying their mana costs. Exile Emergent Ultimatum.

Reliquary Tower

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

Efreet Flamepainter

Double strike
Whenever Efreet Flamepainter deals combat damage to a player, you may cast target instant or sorcery card from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Cecily, Haunted Mage

Your maximum hand size is eleven.
Whenever Cecily, Haunted Mage attacks, you draw a card and you lose 1 life. Then if you have eleven or more cards in your hand, you may cast an instant or sorcery spell from your hand without paying its mana cost.
Friends forever (You can have two commanders if both have friends forever.)

Baleful Strix

Flying, deathtouch
When Baleful Strix enters, draw a card.

Liliana's Standard Bearer

Flash
When Liliana's Standard Bearer enters, draw X cards, where X is the number of creatures that died under your control this turn.

Maelstrom Archangel

Flying
Whenever Maelstrom Archangel deals combat damage to a player, you may cast a spell from your hand without paying its mana cost.

Eerie Ultimatum

Return any number of permanent cards with different names from your graveyard to the battlefield.

Search Party Captain

This spell costs {1} less to cast for each creature you attacked with this turn.
When Search Party Captain enters, draw a card.

Elvish Visionary

When Elvish Visionary enters, draw a card.

Ruinous Ultimatum

Destroy all nonland permanents your opponents control.

Genesis Ultimatum

Look at the top five cards of your library. Put any number of permanent cards from among them onto the battlefield and the rest into your hand. Exile Genesis Ultimatum.

Ice-Fang Coatl

Flash
Flying
When Ice-Fang Coatl enters, draw a card.
Ice-Fang Coatl has deathtouch as long as you control at least three other snow permanents.

Mulldrifter

Flying
When Mulldrifter enters, draw two cards.
Evoke {2}{U} (You may cast this spell for its evoke cost. If you do, it's sacrificed when it enters.)