Blizzard Strix

Flash
Flying
When Blizzard Strix enters the battlefield, if you control another snow permanent, exile target permanent other than Blizzard Strix. Return that card to the battlefield under its owner's control at the beginning of the next end step.

Dream Strix

Flying
When Dream Strix becomes the target of a spell, sacrifice it.
When Dream Strix dies, learn. (You may reveal a Lesson card you own from outside the game and put it into your hand, or discard a card to draw a card.)

Esior, Wardwing Familiar

Flying
Spells your opponents cast that target one or more commanders you control cost {3} more to cast.
Partner (You can have two commanders if both have partner.)

Tidehollow Strix

Flying
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Imbraham, Dean of Theory

Flying
{X}{U}{U}, {T}: Exile the top X cards of your library and put a study counter on each of them. Then you may put a card you own in exile with a study counter on it into your hand.

Kianne, Dean of Substance

{T}: Exile the top card of your library. If it's a land card, put it into your hand. Otherwise, put a study counter on it.
{4}{G}: Create a 0/0 green and blue Fractal creature token. Put a +1/+1 counter on it for each different mana value among nonland cards you own in exile with study counters on them.

Kianne, Dean of Substance // Imbraham, Dean of Theory

Baleful Strix

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

Sky Theater Strix

Flying
Whenever you cast a noncreature spell, Sky Theater Strix gets +1/+0 until end of turn.

Derevi, Empyrial Tactician

Flying
Whenever Derevi, Empyrial Tactician enters the battlefield or a creature you control deals combat damage to a player, you may tap or untap target permanent.
{1}{G}{W}{U}: Put Derevi onto the battlefield from the command zone.

Sidar Kondo of Jamuraa

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
Creatures your opponents control without flying or reach can't block creatures with power 2 or less.
Partner (You can have two commanders if both have partner.)

Parasitic Strix

Flying
When Parasitic Strix enters the battlefield, if you control a black permanent, target player loses 2 life and you gain 2 life.