Thrasios, Triton Hero

{4}: Scry 1, then reveal the top card of your library. If it's a land card, put it onto the battlefield tapped. Otherwise, draw a card.
Partner (You can have two commanders if both have partner.)

Mystic Snake

Flash
When Mystic Snake enters, counter target spell.

Lavinia, Azorius Renegade

Each opponent can't cast noncreature spells with mana value greater than the number of lands that player controls.
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.

Priest of Urabrask

When Priest of Urabrask enters, add {R}{R}{R}.

Cloud of Faeries

Flying
When Cloud of Faeries enters, untap up to two lands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Grand Abolisher

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Aluren

Any player may cast creature spells with mana value 3 or less without paying their mana costs and as though they had flash.

Frilled Mystic

Flash
When Frilled Mystic enters, you may counter target spell.

Akiri, Line-Slinger

First strike, vigilance
Akiri, Line-Slinger gets +1/+0 for each artifact you control.
Partner (You can have two commanders if both have partner.)

Whitemane Lion

Flash
When Whitemane Lion enters, return a creature you control to its owner's hand.

Dream Stalker

When Dream Stalker enters, return a permanent you control to its owner's hand.

Eladamri's Call

Search your library for a creature card, reveal that card, put it into your hand, then shuffle.

Shrieking Drake

Flying
When Shrieking Drake enters, return a creature you control to its owner's hand.

Selvala, Explorer Returned

Parley — {T}: Each player reveals the top card of their library. For each nonland card revealed this way, add {G} and you gain 1 life. Then each player draws a card.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Man-o'-War

When Man-o'-War enters, return target creature to its owner's hand.

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Stonecloaker

Flash
Flying
When Stonecloaker enters, return a creature you control to its owner's hand.
When Stonecloaker enters, exile target card from a graveyard.

Aven Mindcensor

Flash
Flying
If an opponent would search a library, that player searches the top four cards of that library instead.