Halana, Kessig Ranger

Reach
Whenever another creature you control enters, you may pay {2}. When you do, that creature deals damage equal to its power to target creature.
Partner (You can have two commanders if both have partner.)

Alandra, Sky Dreamer

Whenever you draw your second card each turn, create a 2/2 blue Drake creature token with flying.
Whenever you draw your fifth card each turn, Alandra, Sky Dreamer and Drakes you control each get +X/+X until end of turn, where X is the number of cards in your hand.

Tolarian Kraken

Whenever you draw a card, you may pay {1}. When you do, you may tap or untap target creature.

Arwen Undómiel

Whenever you scry, put a +1/+1 counter on target creature.
{4}{G}{U}: Scry 2.

Chance-Met Elves

Whenever you scry, put a +1/+1 counter on Chance-Met Elves. This ability triggers only once each turn.

Lorescale Coatl

Whenever you draw a card, put a +1/+1 counter on Lorescale Coatl.

Galadriel of Lothlórien

Whenever the Ring tempts you, if you chose a creature other than Galadriel of Lothlórien as your Ring-bearer, scry 3.
Whenever you scry, you may reveal the top card of your library. If a land card is revealed this way, put it onto the battlefield tapped.

Sigiled Starfish

{T}: Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Eligeth, Crossroads Augur

Flying
If you would scry a number of cards, draw that many cards instead.
Partner (You can have two commanders if both have partner.)

Elrond, Master of Healing

Whenever you scry, put a +1/+1 counter on each of up to X target creatures, where X is the number of cards looked at while scrying this way.
Whenever a creature you control with a +1/+1 counter on it becomes the target of a spell or ability an opponent controls, you may draw a card.

Psychic Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you scry 2.