Consider

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

Riptide Entrancer

Whenever Riptide Entrancer deals combat damage to a player, you may sacrifice it. If you do, gain control of target creature that player controls. (This effect lasts indefinitely.)
Morph {U}{U} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Agent of Treachery

When Agent of Treachery enters, gain control of target permanent.
At the beginning of your end step, if you control three or more permanents you don't own, draw three cards.

Empress Galina

{U}{U}, {T}: Gain control of target legendary permanent. (This effect lasts indefinitely.)

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Dictate of Erebos

Flash
Whenever a creature you control dies, each opponent sacrifices a creature of their choice.

Betrayal

Enchant creature an opponent controls
Whenever enchanted creature becomes tapped, you draw a card.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Burnished Hart

{3}, Sacrifice this creature: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Invoke the Winds

Gain control of target artifact or creature. Untap it.

Peek

Look at target player's hand.
Draw a card.

Aetherize

Return all attacking creatures to their owner's hand.

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Island

Swamp

Baleful Strix

Flying, deathtouch
When Baleful Strix enters, draw a card.

Sky Diamond

Blatant Thievery

For each opponent, gain control of target permanent that player controls.

Blue Sun's Twilight

Gain control of target creature with mana value X or less. If X is 5 or more, create a token that's a copy of that creature.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Welcome to the Fold

Madness {X}{U}{U} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Gain control of target creature if its toughness is 2 or less. If this spell's madness cost was paid, instead gain control of that creature if its toughness is X or less.

Sakashima's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Target opponent chooses a creature they control. You gain control of it.
• Choose a creature you control. Each other creature you control becomes a copy of that creature until end of turn.

Dark Ritual

Jon Irenicus, Shattered One

At the beginning of your end step, target opponent gains control of up to one target creature you control. Put two +1/+1 counters on it and tap it. It's goaded for the rest of the game and it gains "This creature can't be sacrificed." (It attacks each combat if able and attacks a player other than you if able.)
Whenever a creature you own but don't control attacks, you draw a card.

Entrancing Melody

Gain control of target creature with mana value X.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Portent

Look at the top three cards of target player's library, then put them back in any order. You may have that player shuffle.
Draw a card at the beginning of the next turn's upkeep.

Sol Ring

Mass Manipulation

Gain control of X target creatures and/or planeswalkers.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Dominate

Gain control of target creature with mana value X or less.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Mishra's Bauble

{T}, Sacrifice Mishra's Bauble: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Thalakos Deceiver

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Thalakos Deceiver attacks and isn't blocked, you may sacrifice it. If you do, gain control of target creature. (This effect lasts indefinitely.)

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Tempted by the Oriq

For each opponent, gain control of up to one target creature or planeswalker that player controls with mana value 3 or less.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Lullmage's Domination

This spell costs {3} less to cast if it targets a creature whose controller has eight or more cards in their graveyard.
Gain control of target creature with mana value X.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.