Akrasan Squire

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Advance Scout

First strike
{W}: Target creature gains first strike until end of turn.

Arctic Merfolk

Kicker—Return a creature you control to its owner's hand. (You may return a creature you control to its owner's hand in addition to any other costs as you cast this spell.)
If Arctic Merfolk was kicked, it enters with a +1/+1 counter on it.

Anurid Murkdiver

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Arms of Hadar

Creatures target player controls get -2/-2 until end of turn.

Alabaster Mage

{1}{W}: Target creature you control gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Army of Allah

Attacking creatures get +2/+0 until end of turn.

Apprentice Wizard

Angelsong

Prevent all combat damage that would be dealt this turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Scornful Aether-Lich

{W}{B}: Scornful Aether-Lich gains fear and vigilance until end of turn. (Attacking doesn't cause it to tap, and it can't be blocked except by artifact creatures and/or black creatures.)