Arcanis the Omnipotent

{T}: Draw three cards.
{2}{U}{U}: Return Arcanis to its owner's hand.

Aetherling

{U}: Exile this creature. Return it to the battlefield under its owner's control at the beginning of the next end step.
{U}: This creature can't be blocked this turn.
{1}: This creature gets +1/-1 until end of turn.
{1}: This creature gets -1/+1 until end of turn.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Mairsil, the Pretender

When Mairsil enters, you may exile an artifact or creature card from your hand or graveyard and put a cage counter on it.
Mairsil has all activated abilities of all cards you own in exile with cage counters on them. You may activate each of those abilities only once each turn.

Quicksilver Elemental

{U}: This creature gains all activated abilities of target creature until end of turn. (If any of the abilities use that creature's name, use this creature's name instead.)
You may spend blue mana as though it were mana of any color to pay the activation costs of this creature's abilities.

Torchling

{R}: Untap this creature.
{R}: Target creature blocks this creature this turn if able.
{R}: Change the target of target spell that targets only this creature.
{1}: This creature gets +1/-1 until end of turn.
{1}: This creature gets -1/+1 until end of turn.

Endling

{B}: This creature gains menace until end of turn.
{B}: This creature gains deathtouch until end of turn.
{B}: This creature gains undying until end of turn. (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)
{1}: This creature gets +1/-1 or -1/+1 until end of turn.