Enhanced Awareness

Nimbus of the Isles

Flying (This creature can't be blocked except by creatures with flying or reach.)

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Ashiok, Nightmare Weaver

+2: Exile the top three cards of target opponent's library.
−X: Put a creature card with mana value X exiled with Ashiok, Nightmare Weaver onto the battlefield under your control. That creature is a Nightmare in addition to its other types.
−10: Exile all cards from all opponents' hands and graveyards.

Comparative Analysis

Surge {2}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Target player draws two cards.

Swamp

Staff of the Mind Magus

Whenever you cast a blue spell or an Island you control enters, you gain 1 life.

Siren of the Silent Song

Flying
Inspired — Whenever Siren of the Silent Song becomes untapped, each opponent discards a card, then each opponent mills a card.

Refocus

Marang River Prowler

Marang River Prowler can't block and can't be blocked.
You may cast Marang River Prowler from your graveyard as long as you control a black or green permanent.

Child of Night

Amphin Pathmage

{2}{U}: Target creature can't be blocked this turn.

Vampire Envoy

Flying
Whenever Vampire Envoy becomes tapped, you gain 1 life.

March of the Returned

Return up to two target creature cards from your graveyard to your hand.

Liliana's Indignation

Mill X cards. Target player loses 2 life for each creature card put into your graveyard this way.

Staff of the Death Magus

Whenever you cast a black spell or a Swamp you control enters, you gain 1 life.

Ojutai's Breath

Tap target creature. It doesn't untap during its controller's next untap step.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Kapsho Kitefins

Flying
Whenever Kapsho Kitefins or another creature you control enters, tap target creature an opponent controls.

Rotfeaster Maggot

When Rotfeaster Maggot enters, exile target creature card from a graveyard. You gain life equal to that card's toughness.

Write into Being

Look at the top two cards of your library. Manifest one of those cards, then put the other on the top or bottom of your library. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Shrike Harpy

Flying
Tribute 2 (As this creature enters, an opponent of your choice may put two +1/+1 counters on it.)
When Shrike Harpy enters, if tribute wasn't paid, target opponent sacrifices a creature of their choice.

Sign in Blood

Target player draws two cards and loses 2 life.

Mind Rot

Insatiable Harpy

Negate

Servant of Tymaret

Inspired — Whenever Servant of Tymaret becomes untapped, each opponent loses 1 life. You gain life equal to the life lost this way.
{2}{B}: Regenerate Servant of Tymaret.

Island

Ribbons of Night

Ribbons of Night deals 4 damage to target creature and you gain 4 life. If {U} was spent to cast this spell, draw a card.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Aeronaut Tinkerer

Aeronaut Tinkerer has flying as long as you control an artifact. (It can't be blocked except by creatures with flying or reach.)