Thinking Cap

Equipped creature gets +1/+2.
Equip Detective {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Oliphaunt

Trample
Whenever Oliphaunt attacks, another target creature you control gets +2/+0 and gains trample until end of turn.
Mountaincycling {1} ({1}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)

Smoke Bomb

Flash
All creatures have shroud. (They can't be the targets of spells or abilities.)
At the beginning of your upkeep, sacrifice Smoke Bomb. When you do, target creature you control can't be blocked this turn.

Dream-Thief's Bandana

Whenever equipped creature deals combat damage to a player, look at the top card of their library, then exile it face down. For as long as it remains exiled, you may play it, and mana of any type can be spent to cast that spell.
Equip {1}

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

Hotfoot Gnome

Haste
{T}: Another target creature gains haste until end of turn.

There and Back Again

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Up to one target creature can't block for as long as you control There and Back Again. The Ring tempts you.
II — Search your library for a Mountain card, put it onto the battlefield, then shuffle.
III — Create Smaug, a legendary 6/6 red Dragon creature token with flying, haste, and "When this creature dies, create fourteen Treasure tokens."

Brimstone Roundup

Whenever you cast your second spell each turn, create a 1/1 red Mercenary creature token with "{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."
Plot {2}{R} (You may pay {2}{R} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)

Alexios, Deimos of Kosmos

Trample
Alexios, Deimos of Kosmos attacks each combat if able, can't be sacrificed, and can't attack its owner.
At the beginning of each player's upkeep, that player gains control of Alexios, untaps it, and puts a +1/+1 counter on it. It gains haste until end of turn.

War Squeak

Enchant creature
When War Squeak enters, target creature an opponent controls can't block this turn.
Enchanted creature gets +1/+1 and has haste.

Arcane Signet

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

Sazacap's Brew

Gift a tapped Fish (You may promise an opponent a gift as you cast this spell. If you do, they create a tapped 1/1 blue Fish creature token before its other effects.)
As an additional cost to cast this spell, discard a card.
Target player draws two cards. If the gift was promised, target creature you control gets +2/+0 until end of turn.

Misthios's Fury

Misthios's Fury deals 3 damage to target creature. If you control an Equipment, Misthios's Fury also deals 2 damage to that creature's controller.

Shire Scarecrow

Defender
{1}: Add one mana of any color. Activate only once each turn.

Tectonic Hazard

Tectonic Hazard deals 1 damage to each opponent and each creature they control.

Adrestia

Islandwalk (This creature can't be blocked as long as defending player controls an Island.)
Whenever Adrestia attacks, if an Assassin crewed it this turn, draw a card. Adrestia becomes an Assassin in addition to its other types until end of turn.
Crew 1

Sol Ring

Knollspine Dragon

Flying
When Knollspine Dragon enters, you may discard your hand and draw cards equal to the damage dealt to target opponent this turn.

Ranger's Firebrand

Ranger's Firebrand deals 2 damage to any target. The Ring tempts you.

Fire of Orthanc

Destroy target artifact or land. Creatures without flying can't block this turn.

Shiny Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Smite the Deathless

Smite the Deathless deals 3 damage to target creature. That creature loses indestructible until end of turn. If that creature would die this turn, exile it instead.

Sting, the Glinting Dagger

Equipped creature gets +1/+1 and has haste.
At the beginning of each combat, untap equipped creature.
Equipped creature has first strike as long as it's blocking or blocked by a Goblin or Orc.
Equip {2}

Headsplitter

When Headsplitter enters, create a 1/1 black Assassin creature token with menace, then attach Headsplitter to it.
Equipped creature gets +1/+0.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

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.)

Quarrel's End

As an additional cost to cast this spell, discard a card.
Draw two cards and create a 1/1 white Human Soldier creature token.

Fires of Mount Doom

When Fires of Mount Doom enters, it deals 2 damage to target creature an opponent controls. Destroy all Equipment attached to that creature.
{2}{R}: Exile the top card of your library. You may play that card this turn. When you play a card this way, Fires of Mount Doom deals 2 damage to each player.

Monastery Raid

Freerunning {X}{R} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Exile the top two cards of your library. If this spell's freerunning cost was paid, exile the top X cards of your library instead. You may play the exiled cards until the end of your next turn.

Excalibur, Sword of Eden

This spell costs {X} less to cast, where X is the total mana value of historic permanents you control. (Artifacts, legendaries, and Sagas are historic.)
Equipped creature gets +10/+0 and has vigilance.
Equip legendary creature {2}

Ent-Draught Basin

{X}, {T}: Put a +1/+1 counter on target creature with power X. Activate only as a sorcery.

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Access Tunnel

{T}: Add {C}.
{3}, {T}: Target creature with power 3 or less can't be blocked this turn.

Origin of the Hidden Ones

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Origin of the Hidden Ones deals 4 damage to any target.
II — Create two 1/1 black Assassin creature tokens with menace.
III — Whenever an Assassin you control attacks this turn, create a 1/1 black Assassin creature token with menace that's tapped and attacking.

Hidden Footblade

Flash
When Hidden Footblade enters, attach it to target creature you control. That creature gains first strike until end of turn.
Equipped creature gets +1/+0 and has haste.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Mountain

Towering Viewpoint

Defender, reach
Leap of Faith — {3}: Target creature gains flying until end of turn.

Gold Pan

When Gold Pan enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
Equipped creature gets +1/+1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Hidden Blade

Flash
When Hidden Blade enters, attach it to target creature you control. If that creature is an Assassin, it gains deathtouch until end of turn.
Equipped creature gets +1/+0 and has first strike.
Equip {2}

Khârn the Betrayer

Berzerker — Khârn the Betrayer attacks or blocks each combat if able.
Sigil of Corruption — When you lose control of Khârn the Betrayer, draw two cards.
The Betrayer — If damage would be dealt to Khârn the Betrayer, prevent that damage and an opponent of your choice gains control of it.

Runaway Boulder

Flash
When Runaway Boulder enters, it deals 6 damage to target creature an opponent controls.
Cycling {2} ({2}, Discard this card: Draw a card.)

Starforged Sword

Gift a tapped Fish (You may promise an opponent a gift as you cast this spell. If you do, when it enters, they create a tapped 1/1 blue Fish creature token.)
When Starforged Sword enters, if the gift was promised, attach Starforged Sword to target creature you control.
Equipped creature gets +3/+3 and loses flying.
Equip {3}

Barrow-Blade

Equipped creature gets +1/+1.
Whenever equipped creature blocks or becomes blocked by a creature, that creature loses all abilities until end of turn.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Oasis Gardener

When Oasis Gardener enters, you gain 2 life.
{T}: Add one mana of any color.

Lothlórien Blade

Whenever equipped creature attacks, it deals damage equal to its power to target creature defending player controls.
Equip Elf {2}
Equip {5}

Chaos Terminator Lord

Lord of Chaos — At the beginning of combat on your turn, another target creature you control gains double strike until end of turn.

Lightning Greaves

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

Spartan Veteran

During your turn, Spartan Veteran has first strike. (It deals combat damage before creatures without first strike.)
{2}: Spartan Veteran gets +1/+0 until end of turn.

Quick Draw

Target creature you control gets +1/+1 and gains first strike until end of turn. Creatures target opponent controls lose first strike and double strike until end of turn.

Haradrim Spearmaster

Reach
At the beginning of combat on your turn, another target creature you control gets +1/+0 until end of turn.

Expose the Culprit

Choose one or both —
• Turn target face-down creature face up.
• Exile any number of face-up creatures you control with disguise in a face-down pile, shuffle that pile, then cloak them. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Fiery Inscription

When Fiery Inscription enters, the Ring tempts you.
Whenever you cast an instant or sorcery spell, Fiery Inscription deals 2 damage to each opponent.

Rush the Room

Target creature gets +1/+0 and gains first strike until end of turn. If it's a Goblin or Orc, it also gains haste until end of turn.

Fiendlash

Equipped creature gets +2/+0 and has reach.
Whenever equipped creature is dealt damage, it deals damage equal to its power to target player or planeswalker.
Equip {2}{R}

Scourge of the Throne

Flying
Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Whenever Scourge of the Throne attacks for the first time each turn, if it's attacking the player with the most life or tied for most life, untap all attacking creatures. After this phase, there is an additional combat phase.

Nazgûl Battle-Mace

Equipped creature has menace, deathtouch, annihilator 1, and "Whenever an opponent sacrifices a nontoken permanent, put that card onto the battlefield under your control unless that player pays 3 life." (Whenever a creature with annihilator 1 attacks, defending player sacrifices a permanent of their choice.)
Equip {3}

Fanged Flames

Devoid (This card has no color.)
Fanged Flames deals 4 damage to target creature or planeswalker. If that creature or planeswalker would die this turn, exile it instead.

Artist's Talent

(Gain the next level as a sorcery to add its ability.)
Whenever you cast a noncreature spell, you may discard a card. If you do, draw a card.
{2}{R}: Level 2
Noncreature spells you cast cost {1} less to cast.
{2}{R}: Level 3
If a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Breaking of the Fellowship

Target creature an opponent controls deals damage equal to its power to another target creature that player controls. The Ring tempts you.

Valley Rally

Gift a Food (You may promise an opponent a gift as you cast this spell. If you do, they create a Food token before its other effects. It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")
Creatures you control get +2/+0 until end of turn. If the gift was promised, target creature you control gains first strike until end of turn.

Cavern-Hoard Dragon

This spell costs {X} less to cast, where X is the greatest number of artifacts an opponent controls.
Flying, trample, haste
Whenever Cavern-Hoard Dragon deals combat damage to a player, you create a Treasure token for each artifact that player controls.

Commander's Sphere

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

Bilbo's Ring

During your turn, equipped creature has hexproof and can't be blocked.
Whenever equipped creature attacks alone, you draw a card and you lose 1 life.
Equip Halfling {1} ({1}: Attach to target Halfling you control. Equip only as a sorcery.)
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Prickly Pair

When Prickly Pair enters, create a 1/1 red Mercenary creature token with "{T}: Target creature you control gets +1/+0 until end of turn. Activate only as a sorcery."

Gimli's Axe

Equipped creature gets +3/+0.
As long as equipped creature is legendary, it has menace. (It can't be blocked except by two or more creatures.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Fellwar Stone

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

Labyrinth Adversary

Trample (This creature can deal excess combat damage to the player it's attacking.)
Whenever you attack, you may pay {1}{R}. When you do, target creature can't block this turn.