Thassa, God of the Sea

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Sword Coast Sailor

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, this creature can't be blocked this turn."

Esior, Wardwing Familiar

Flying
Spells your opponents cast that target one or more commanders you control cost {3} more to cast.
Partner (You can have two commanders if both have partner.)

Three Dreams

Search your library for up to three Aura cards with different names, reveal them, put them into your hand, then shuffle.

Rebuff the Wicked

Counter target spell that targets a permanent you control.

Trophy Mage

When Trophy Mage enters, you may search your library for an artifact card with mana value 3, reveal it, put it into your hand, then shuffle.

Fevered Visions

At the beginning of each player's end step, that player draws a card. If the player is your opponent and has four or more cards in hand, Fevered Visions deals 2 damage to that player.

Brotherhood Regalia

Equipped creature has ward {2}, is an Assassin in addition to its other types, and can't be blocked.
Equip legendary creature {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Dictate of Kruphix

Flash
At the beginning of each player's draw step, that player draws an additional card.

Guild Artisan

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, you create two Treasure tokens." (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Sundown Pass

Sundown Pass enters tapped unless you control two or more other lands.
{T}: Add {R} or {W}.

Tavern Brawler

Commander creatures you own have "At the beginning of your upkeep, exile the top card of your library. This creature gets +X/+0 until end of turn, where X is that card's mana value. You may play that card this turn."

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Witch's Clinic

{T}: Add {C}.
{2}, {T}: Target commander gains lifelink until end of turn.

Mystic Gate

{T}: Add {C}.
{W/U}, {T}: Add {W}{W}, {W}{U}, or {U}{U}.

Fabricate

Search your library for an artifact card, reveal it, put it into your hand, then shuffle.

Fighter Class

(Gain the next level as a sorcery to add its ability.)
When Fighter Class enters, search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
{1}{R}{W}: Level 2
Equip abilities you activate cost {2} less to activate.
{3}{R}{W}: Level 3
Whenever a creature you control attacks, up to one target creature blocks it this combat if able.

Steelshaper's Gift

Search your library for an Equipment card, reveal that card, put it into your hand, then shuffle.

Plains

Ghostly Prison

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

Whirlwind of Thought

Whenever you cast a noncreature spell, draw a card.

Trailblazer's Boots

Equipped creature has nonbasic landwalk. (It can't be blocked as long as defending player controls a nonbasic land.)
Equip {2}

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Heliod's Pilgrim

When Heliod's Pilgrim enters, you may search your library for an Aura card, reveal it, put it into your hand, then shuffle.

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.)

Academy Ruins

{T}: Add {C}.
{1}{U}, {T}: Put target artifact card from your graveyard on top of your library.

Ishai, Ojutai Dragonspeaker

Flying
Whenever an opponent casts a spell, put a +1/+1 counter on Ishai, Ojutai Dragonspeaker.
Partner (You can have two commanders if both have partner.)

Hall of Heliod's Generosity

{T}: Add {C}.
{1}{W}, {T}: Put target enchantment card from your graveyard on top of your library.

Kami of the Crescent Moon

At the beginning of each player's draw step, that player draws an additional card.

Open the Armory

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Deserted Beach

Deserted Beach enters tapped unless you control two or more other lands.
{T}: Add {W} or {U}.

Azorius Signet

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Loyal Drake

Flying
Lieutenant — At the beginning of combat on your turn, if you control your commander, draw a card.

Izzet Signet

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.)

Windborn Muse

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

Stoneforge Mystic

When Stoneforge Mystic enters, you may search your library for an Equipment card, reveal it, put it into your hand, then shuffle.
{1}{W}, {T}: You may put an Equipment card from your hand onto the battlefield.

Arcane Signet

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

Boros Signet

Mithril Coat

Flash
Indestructible
When Mithril Coat enters, attach it to target legendary creature you control.
Equipped creature has indestructible.
Equip {3}

Rograkh, Son of Rohgahh

First strike, menace, trample
Partner (You can have two commanders if both have partner.)

All That Glitters

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

Minas Tirith

Minas Tirith enters tapped unless you control a legendary creature.
{T}: Add {W}.
{1}{W}, {T}: Draw a card. Activate only if you attacked with two or more creatures this turn.

Jeska, Thrice Reborn

Jeska, Thrice Reborn enters with a loyalty counter on her for each time you've cast a commander from the command zone this game.
0: Choose target creature. Until your next turn, if that creature would deal combat damage to one of your opponents, it deals triple that damage to that player instead.
−X: Jeska, Thrice Reborn deals X damage to each of up to three targets.
Jeska, Thrice Reborn can be your commander.
Partner

Reliquary Tower

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

Training Center

Training Center enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

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.

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Dovin's Veto

This spell can't be countered.
Counter target noncreature spell.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Idyllic Tutor

Search your library for an enchantment card, reveal it, put it into your hand, then shuffle.

Ferrous Lake

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Pearl Medallion

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

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

Rhystic Study

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

Permission Denied

Counter target noncreature spell. Your opponents can't cast noncreature spells this turn.

Tribute Mage

When Tribute Mage enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.

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.

Noble Heritage

Commander creatures you own have "When this creature enters and at the beginning of your upkeep, each player may put two +1/+1 counters on a creature they control. For each opponent who does, you gain protection from that player until your next turn." (You can't be targeted, dealt damage, or enchanted by anything controlled by that player.)

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Reyav, Master Smith

Whenever a creature you control that's enchanted or equipped attacks, that creature gains double strike until end of turn.

Spectator Seating

Spectator Seating enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Skycloud Expanse

Rugged Prairie

{T}: Add {C}.
{R/W}, {T}: Add {R}{R}, {R}{W}, or {W}{W}.

Counterspell

Enlightened Tutor

Search your library for an artifact or enchantment card, reveal it, then shuffle and put that card on top.

Island

Negate

Sapphire Medallion

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

Propaganda

Idolized

Enchant creature
Enchanted creature has "Whenever this creature attacks alone, it gets +X/+X until end of turn, where X is the number of nonland permanents you control."

Talisman of Progress

{T}: Add {C}.
{T}: Add {W} or {U}. Talisman of Progress deals 1 damage to you.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Howling Mine

At the beginning of each player's draw step, if Howling Mine is untapped, that player draws an additional card.

Bastion Protector

Commander creatures you control get +2/+2 and have indestructible.

Cascade Bluffs

{T}: Add {C}.
{U/R}, {T}: Add {U}{U}, {U}{R}, or {R}{R}.

Stormcarved Coast

Stormcarved Coast enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Sea of Clouds

Sea of Clouds enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Sunscorched Divide

Horn of Greed

Whenever a player plays a land, that player draws a card.

Nettlecyst

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +1/+1 for each artifact and/or enchantment you control.
Equip {2}

Flaming Fist

Commander creatures you own have "Whenever this creature attacks, it gains double strike until end of turn."

Sol Ring

Command Tower

Mountain

Blackblade Reforged

Equipped creature gets +1/+1 for each land you control.
Equip legendary creature {3}
Equip {7}