Aerathi Berserker

Rampage 3 (Whenever this creature becomes blocked, it gets +3/+3 until end of turn for each creature blocking it beyond the first.)

Ancient Hydra

Fading 5 (This creature enters with five fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
{1}, Remove a fade counter from Ancient Hydra: It deals 1 damage to any target.

Adarkar Valkyrie

Flying, vigilance
{T}: When target creature other than Adarkar Valkyrie dies this turn, return that card to the battlefield under your control.

Alexander Clamilton

Whenever you cast a wordy spell, scry 2. (A spell is wordy if it has four or more lines of rules text.)
{1}{R}, {T}: Choose target creature you don't control. Reveal the top card of your library. Alexander Clamilton gets +X/+0 until end of turn, where X is the number of lines of rules text of the revealed card. Alexander Clamilton fights that creature.

Aladdin

{1}{R}{R}, {T}: Gain control of target artifact for as long as you control Aladdin.

Ancient Kavu

{2}: Ancient Kavu becomes colorless until end of turn.

Aggressive Mammoth

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Other creatures you control have trample.

Alpine Watchdog

Vigilance (Attacking doesn't cause this creature to tap.)

Akron Legionnaire

Except for creatures named Akron Legionnaire and artifact creatures, creatures you control can't attack.