Ambling Stormshell

Ward {2}
Whenever this creature attacks, put three stun counters on it and draw three cards. (If a permanent with a stun counter would become untapped, remove one from it instead.)
Whenever you cast a Turtle spell, untap this creature.

Aegis Sculptor

Flying
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
At the beginning of your upkeep, you may exile two cards from your graveyard. If you do, put a +1/+1 counter on this creature.

Airtight Alibi

Flash
Enchant creature
When this Aura enters, untap enchanted creature. It gains hexproof until end of turn. If it's suspected, it's no longer suspected.
Enchanted creature gets +2/+2 and can't become suspected.

Helga, Skittish Seer

Whenever you cast a creature spell with mana value 4 or greater, you draw a card, gain 1 life, and put a +1/+1 counter on Helga.
{T}: Add X mana of any one color, where X is Helga's power. Spend this mana only to cast creature spells with mana value 4 or greater or creature spells with {X} in their mana costs.