Consider

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

Diabolic Edict

Target player sacrifices a creature of their choice.

Mental Note

Ice Tunnel

({T}: Add {U} or {B}.)
Ice Tunnel enters tapped.

Fallaji Archaeologist

When Fallaji Archaeologist 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 Fallaji Archaeologist. (To mill a card, put the top card of your library into your graveyard.)

Contaminated Aquifer

({T}: Add {U} or {B}.)
Contaminated Aquifer enters tapped.

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}.)

Chainer's Edict

Target player sacrifices a creature of their choice.
Flashback {5}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Counterspell

Cast Down

Snow-Covered Island

Spell Pierce

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

Shrivel

All creatures get -1/-1 until end of turn.

Thought Scour

Target player mills two cards.
Draw a card.

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Brainstorm

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

Gurmag Angler

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

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.)