Trickbind

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Counter target activated or triggered ability. If a permanent's ability is countered this way, activated abilities of that permanent can't be activated this turn. (Mana abilities can't be targeted.)

Kaseto, Orochi Archmage

{G}{U}: Target creature can't be blocked this turn. If that creature is a Snake, it gets +2/+2 until end of turn.

Defabricate

Choose one —
• Counter target artifact or enchantment spell. If a spell is countered this way, exile it instead of putting it into its owner's graveyard.
• Counter target activated or triggered ability.

Hushbringer

Flying, lifelink
Creatures entering or dying don't cause abilities to trigger.

Samwise the Stouthearted

Flash
When Samwise enters, choose up to one target permanent card in your graveyard that was put there from the battlefield this turn. Return it to your hand. Then the Ring tempts you.

Padeem, Consul of Innovation

Artifacts you control have hexproof. (They can't be the targets of spells or abilities your opponents control.)
At the beginning of your upkeep, if you control the artifact with the greatest mana value or tied for the greatest mana value, draw a card.

Tempting Wurm

When this creature enters, each opponent may put any number of artifact, creature, enchantment, and/or land cards from their hand onto the battlefield.

Tale's End

Counter target activated ability, triggered ability, or legendary spell.

Tribute Mage

When this creature enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

Leveler

When this creature enters, exile all cards from your library.

Alora, Merry Thief

Whenever you attack, up to one target attacking creature can't be blocked this turn. Return that creature to its owner's hand at the beginning of the next end step.
Choose a Background (You can have a Background as a second commander.)

Hushwing Gryff

Flash
Flying
Creatures entering don't cause abilities to trigger.

Torpor Orb

Creatures entering don't cause abilities to trigger.

Hunted Phantasm

This creature can't be blocked.
When this creature enters, target opponent creates five 1/1 red Goblin creature tokens.

Wormfang Manta

Flying
When this creature enters, you skip your next turn.
When this creature leaves the battlefield, you take an extra turn after this one.

Doorkeeper Thrull

Flash
Flying
Artifacts and creatures entering don't cause abilities to trigger.

Supreme Exemplar

Flying
Champion an Elemental (When this enters, sacrifice it unless you exile another Elemental you control. When this leaves the battlefield, that card returns to the battlefield.)

Ovinomancer

When this creature enters, sacrifice it unless you return three basic lands you control to their owner's hand.
{T}, Return this creature to its owner's hand: Destroy target creature. It can't be regenerated. That creature's controller creates a 0/1 green Sheep creature token.

Sky Swallower

Flying
When this creature enters, target opponent gains control of all other permanents you control.

Ioreth of the Healing House

{T}: Untap another target permanent.
{T}: Untap two other target legendary creatures.

Roon of the Hidden Realm

Vigilance, trample
{2}, {T}: Exile another target creature. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Stifle

Counter target activated or triggered ability. (Mana abilities can't be targeted.)