Rhystic Study

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

Hellkite Courser

Flying
When Hellkite Courser enters the battlefield, you may put a commander you own from the command zone onto the battlefield. It gains haste. Return it to the command zone at the beginning of the next end step.

The First Sliver

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)
Sliver spells you cast have cascade.

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Unnatural Selection

{1}: Choose a creature type other than Wall. Target creature becomes that type until end of turn.

Yuriko, the Tiger's Shadow

Commander ninjutsu {U}{B} ({U}{B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand or the command zone tapped and attacking.)
Whenever a Ninja you control deals combat damage to a player, reveal the top card of your library and put that card into your hand. Each opponent loses life equal to that card's mana value.

Skyshroud Poacher

{3}, {T}: Search your library for an Elf permanent card, put it onto the battlefield, then shuffle.

Manaweft Sliver

Sliver creatures you control have "{T}: Add one mana of any color."

Hibernation Sliver

All Slivers have "Pay 2 life: Return this permanent to its owner's hand."

Cryptic Gateway

Tap two untapped creatures you control: You may put a creature card from your hand that shares a creature type with each creature tapped this way onto the battlefield.

Mothdust Changeling

Changeling (This card is every creature type.)
Tap an untapped creature you control: Mothdust Changeling gains flying until end of turn.

Gilt-Leaf Archdruid

Whenever you cast a Druid spell, you may draw a card.
Tap seven untapped Druids you control: Gain control of all lands target player controls.

Unholy Grotto

{T}: Add {C}.
{B}, {T}: Put target Zombie card from your graveyard on top of your library.

Murmuring Bosk

({T}: Add {G}.)
As Murmuring Bosk enters the battlefield, you may reveal a Treefolk card from your hand. If you don't, Murmuring Bosk enters the battlefield tapped.
{T}: Add {W} or {B}. Murmuring Bosk deals 1 damage to you.

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters the battlefield, choose a creature type.
Whenever another creature of the chosen type enters the battlefield under your control, put a +1/+1 counter on Bloodline Pretender.

Seraph Sanctuary

When Seraph Sanctuary enters the battlefield, you gain 1 life.
Whenever an Angel enters the battlefield under your control, you gain 1 life.
{T}: Add {C}.

Priest of Titania

{T}: Add {G} for each Elf on the battlefield.

Wirewood Symbiote

Return an Elf you control to its owner's hand: Untap target creature. Activate only once each turn.

Arcane Adaptation

As Arcane Adaptation enters the battlefield, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Reaper King

({2/W} can be paid with any two mana or with {W}. This card's mana value is 10.)
Other Scarecrow creatures you control get +1/+1.
Whenever another Scarecrow enters the battlefield under your control, destroy target permanent.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon, the Boundless enters the battlefield, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.