Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Contaminated Aquifer

({T}: Add {U} or {B}.)
This land enters tapped.

Dispel

Agony Warp

Target creature gets -3/-0 until end of turn.
Target creature gets -0/-3 until end of turn.

Unseal the Necropolis

Each player mills three cards. Then you return up to two creature cards from your graveyard to your hand. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Cast Down

Counterspell

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

Foil

You may discard an Island card and another card rather than pay this spell's mana cost.
Counter target spell.

Unexpected Fangs

Put a +1/+1 counter and a lifelink counter on target creature.

Ice Tunnel

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Island

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Tolarian Terror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

Fallaji Archaeologist

When this creature enters, mill three cards. You may put a noncreature, nonland card from among the cards milled this way into your hand. If you don't, put a +1/+1 counter on this creature. (To mill a card, put the top card of your library into your graveyard.)

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Mental Note

Thought Scour

Target player mills two cards.
Draw a card.

Suffocating Fumes

Creatures your opponents control get -1/-1 until end of turn.
Cycling {2} ({2}, Discard this card: Draw a card.)

Snuff Out

If you control a Swamp, you may pay 4 life rather than pay this spell's mana cost.
Destroy target nonblack creature. It can't be regenerated.