Derevi, Empyrial Tactician

Flying
When Derevi enters and whenever 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.

Baleful Strix

Flying, deathtouch
When this creature enters, draw a card.

Tidehollow Strix

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

Dream Strix

Flying
When this creature becomes the target of a spell, sacrifice it.
When this creature 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.)

Sky Theater Strix

Flying
Whenever you cast a noncreature spell, this creature gets +1/+0 until end of turn.

Parasitic Strix

Flying
When this creature enters, if you control a black permanent, target player loses 2 life and you gain 2 life.

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.)

Blizzard Strix

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

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.)

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.