Watcher of the Spheres

Flying
Creature spells with flying you cast cost {1} less to cast.
Whenever another creature you control with flying enters, Watcher of the Spheres gets +1/+1 until end of turn.

Thoughtcast

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

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Curiosity Crafter

Flying
You have no maximum hand size.
Whenever a creature token you control deals combat damage to a player, draw a card.

Blind Obedience

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Artifacts and creatures your opponents control enter tapped.

Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Anointed Procession

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Favorable Winds

Creatures you control with flying get +1/+1.

Vampiric Link

Enchant creature
Whenever enchanted creature deals damage, you gain that much life.

Helm of the Gods

Equipped creature gets +1/+1 for each enchantment you control.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Intangible Virtue

Creature tokens you control get +1/+1 and have vigilance.

All That Glitters

Enchant creature
Enchanted creature gets +1/+1 for each artifact and/or enchantment you control.

Azorius Signet

Hyena Umbra

Enchant creature
Enchanted creature gets +1/+1 and has first strike.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Bident of Thassa

Whenever a creature you control deals combat damage to a player, you may draw a card.
{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Aqueous Form

Enchant creature
Enchanted creature can't be blocked.
Whenever enchanted creature attacks, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Coastal Piracy

Whenever a creature you control deals combat damage to an opponent, you may draw a card.

Greasefang, Okiba Boss

At the beginning of combat on your turn, return target Vehicle card from your graveyard to the battlefield. It gains haste. Return it to its owner's hand at the beginning of your next end step.

Curiosity

Enchant creature
Whenever enchanted creature deals damage to an opponent, you may draw a card.

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice Idol of Oblivion: Create a 10/10 colorless Eldrazi creature token.

Spirit Link

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Whenever enchanted creature deals damage, you gain that much life.

Utter End

Etherium Sculptor

Artifact spells you cast cost {1} less to cast.

Spirit Mantle

Enchant creature
Enchanted creature gets +1/+1 and has protection from creatures.

Grafdigger's Cage

Creature cards in graveyards and libraries can't enter the battlefield.
Players can't cast spells from graveyards or libraries.

Authority of the Consuls

Creatures your opponents control enter tapped.
Whenever a creature an opponent controls enters, you gain 1 life.

Esper Sentinel

Whenever an opponent casts their first noncreature spell each turn, draw a card unless that player pays {X}, where X is Esper Sentinel's power.

Weatherlight

Flying
Whenever Weatherlight deals combat damage to a player, look at the top five cards of your library. You may reveal a historic card from among them and put it into your hand. Put the rest on the bottom of your library in a random order. (Artifacts, legendaries, and Sagas are historic.)
Crew 3

Prodigy's Prototype

Whenever one or more Vehicles you control attack, create a 1/1 colorless Pilot creature token with "This creature crews Vehicles as though its power were 2 greater."
Crew 2 (Tap any number of creatures you control with total power 2 or more: This Vehicle becomes an artifact creature until end of turn.)

Ethereal Armor

Enchant creature
Enchanted creature gets +1/+1 for each enchantment you control and has first strike.

Reconnaissance Mission

Whenever a creature you control deals combat damage to a player, you may draw a card.
Cycling {2} ({2}, Discard this card: Draw a card.)

Shorikai, Genesis Engine

{1}, {T}: Draw two cards, then discard a card. Create a 1/1 colorless Pilot creature token with "This creature crews Vehicles as though its power were 2 greater."
Crew 8 (Tap any number of creatures you control with total power 8 or more: This Vehicle becomes an artifact creature until end of turn.)
Shorikai, Genesis Engine can be your commander.

Alela, Artful Provocateur

Flying, deathtouch, lifelink
Other creatures you control with flying get +1/+0.
Whenever you cast an artifact or enchantment spell, create a 1/1 blue Faerie creature token with flying.

Empyrean Eagle

Flying
Other creatures you control with flying get +1/+1.

Teferi's Ageless Insight

If you would draw a card except the first one you draw in each of your draw steps, draw two cards instead.

Hotshot Mechanic

Hotshot Mechanic crews Vehicles as though its power were 2 greater.

Thought Monitor

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)
Flying
When Thought Monitor enters, draw two cards.

Fracture

Destroy target artifact, enchantment, or planeswalker.

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Soul Warden

Whenever another creature enters, you gain 1 life.

Arcane Signet

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

Vedalken Archmage

Whenever you cast an artifact spell, draw a card.

Clock of Omens

Tap two untapped artifacts you control: Untap target artifact.

Counterspell

Smuggler's Copter

Flying
Whenever Smuggler's Copter attacks or blocks, you may draw a card. If you do, discard a card.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)