Consider

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

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

Sol Ring

Drake Umbra

Enchant creature
Enchanted creature gets +3/+3 and has flying.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Rhystic Study

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

Fellwar Stone

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

Shimmering Efreet

Flying
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)
Whenever this creature phases in, target creature phases out. (It phases in before its controller untaps during their next untap step.)

Jeskai Runemark

Enchant creature
Enchanted creature gets +2/+2.
Enchanted creature has flying as long as you control a red or white permanent.

Midnight Clock

{T}: Add {U}.
{2}{U}: Put an hour counter on this artifact.
At the beginning of each upkeep, put an hour counter on this artifact.
When the twelfth hour counter is put on this artifact, shuffle your hand and graveyard into your library, then draw seven cards. Exile this artifact.

Counterspell

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Betrayal

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

Sisay's Ring

Shimmer

As this enchantment enters, choose a land type.
Each land of the chosen type has phasing. (It phases in or out before its controller untaps during each of their untap steps. While it's phased out, it's treated as though it doesn't exist.)

Switcheroo

Exchange control of two target creatures.

Ornithopter of Paradise

Island

Sunder

Svyelunite Temple

This land enters tapped.
{T}: Add {U}.
{T}, Sacrifice this land: Add {U}{U}.

Intervene

Counter target spell that targets a creature.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

Aether Tunnel

Enchant creature
Enchanted creature gets +1/+0 and can't be blocked.

Oboro, Palace in the Clouds

{T}: Add {U}.
{1}: Return Oboro to its owner's hand.

Sky Diamond

This artifact enters tapped.
{T}: Add {U}.

Daring Thief

Inspired — Whenever this creature becomes untapped, you may exchange control of target nonland permanent you control and target permanent an opponent controls that shares a card type with it.

Thran Dynamo

Worldslayer

Whenever equipped creature deals combat damage to a player, destroy all permanents other than this Equipment.
Equip {5} ({5}: Attach to target creature you control. Equip only as a sorcery.)

Slip Out the Back

Put a +1/+1 counter on target creature. It phases out. (Treat it and anything attached to it as though they don't exist until its controller's next turn.)

Sol Talisman

Suspend 3—{1} (Rather than cast this card from your hand, pay {1} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
{T}: Add {C}{C}.

Stonespeaker Crystal

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Exile any number of target players' graveyards. Draw a card.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Surveyor's Scope

{T}, Exile this artifact: Search your library for up to X basic land cards, where X is the number of players who control at least two more lands than you. Put those cards onto the battlefield, then shuffle.

Cartouche of Knowledge

Enchant creature you control
When this Aura enters, draw a card.
Enchanted creature gets +1/+1 and has flying.

Confound

Counter target spell that targets a creature.
Draw a card.

Propaganda

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

Isolated Watchtower

{T}: Add {C}.
{2}, {T}: Scry 1, then you may reveal the top card of your library. If a basic land card is revealed this way, put it onto the battlefield tapped. Activate only if an opponent controls at least two more lands than you.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

Storm Cauldron

Each player may play an additional land during each of their turns.
Whenever a land is tapped for mana, return it to its owner's hand.

Ur-Golem's Eye

March of Swirling Mist

As an additional cost to cast this spell, you may exile any number of blue cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Up to X target creatures phase out. (While they're phased out, they're treated as though they don't exist. Each one phases in before its controller untaps during their next untap step.)

Mana Breach

Whenever a player casts a spell, that player returns a land they control to its owner's hand.

Shifting Grift

Spree (Choose one or more additional costs.)
+ {2} — Exchange control of two target creatures.
+ {1} — Exchange control of two target artifacts.
+ {1} — Exchange control of two target enchantments.

Arcane Signet

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

Mystic Sanctuary

({T}: Add {U}.)
This land enters tapped unless you control three or more other Islands.
When this land enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Commander's Sphere

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

Spawnbroker

When this creature enters, you may exchange control of target creature you control and target creature with power less than or equal to that creature's power an opponent controls.

Taniwha

Trample
Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)
At the beginning of your upkeep, all lands you control phase out. (They phase in before you untap during your next untap step.)

Cryptic Command

Choose two —
• Counter target spell.
• Return target permanent to its owner's hand.
• Tap all creatures your opponents control.
• Draw a card.

Auramancer's Guise

Enchant creature
Enchanted creature gets +2/+2 for each Aura attached to it and has vigilance.

Land Equilibrium

If an opponent who controls at least as many lands as you do would put a land onto the battlefield, that player instead puts that land onto the battlefield then sacrifices a land of their choice.

Serum Visions

Eldrazi Conscription

Enchant creature
Enchanted creature gets +10/+10 and has trample and annihilator 2. (Whenever it attacks, defending player sacrifices two permanents of their choice.)

Chromeshell Crab

Morph {4}{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.)
When this creature is turned face up, you may exchange control of target creature you control and target creature an opponent controls.

Ward of Bones

Each opponent who controls more creatures than you can't cast creature spells. The same is true for artifacts and enchantments.
Each opponent who controls more lands than you can't play lands.

Metamorphic Alteration

Enchant creature
As this Aura enters, choose a creature.
Enchanted creature is a copy of the chosen creature.

Archmage's Charm

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Keep Safe

Counter target spell that targets a permanent you control.
Draw a card.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard this card: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Hedron Archive

{T}: Add {C}{C}.
{2}, {T}, Sacrifice this artifact: Draw two cards.

Archway of Innovation

This land enters tapped unless you control an Island.
{T}: Add {U}.
{U}, {T}: The next spell you cast this turn has improvise. (Your artifacts can help cast that spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Replicating Ring

{T}: Add one mana of any color.
At the beginning of your upkeep, put a night counter on this artifact. Then if it has eight or more night counters on it, remove all of them and create eight colorless snow artifact tokens named Replicated Ring with "{T}: Add one mana of any color."

True Polymorph

Target artifact or creature becomes a copy of another target artifact or creature.

Overburden

Whenever a player puts a nontoken creature onto the battlefield, that player returns a land they control to its owner's hand.

Thoughtcast

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Draw two cards.

Faerie Mastermind

Flash
Flying
Whenever an opponent draws their second card each turn, you draw a card.
{3}{U}: Each player draws a card.

Puca's Mischief

At the beginning of your upkeep, you may exchange control of target nonland permanent you control and target nonland permanent an opponent controls with equal or lesser mana value.

Ponder

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