Boromir, Warden of the Tower

Vigilance
Whenever an opponent casts a spell, if no mana was spent to cast it, counter that spell.
Sacrifice Boromir, Warden of the Tower: Creatures you control gain indestructible until end of turn. The Ring tempts you.

Boros Elite

Battalion — Whenever Boros Elite and at least two other creatures attack, Boros Elite gets +2/+2 until end of turn.

Dalek Squadron

Menace
Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Rosnakht, Heir of Rohgahh

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Heroic — Whenever you cast a spell that targets Rosnakht, Heir of Rohgahh, create a 0/1 red Kobold creature token named Kobolds of Kher Keep.

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Commissar Severina Raine

Leading from the Front — Whenever Commissar Severina Raine attacks, each opponent loses X life, where X is the number of other attacking creatures.
Summary Execution — {2}, Sacrifice another creature: You gain 2 life and draw a card.

Horn of the Mark

Whenever two or more creatures you control attack a player, look at the top five cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

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.)

Phyrexian Dragon Engine

Double strike
When Phyrexian Dragon Engine enters from your graveyard, you may discard your hand. If you do, draw three cards.
Unearth {3}{R}{R}
(Melds with Mishra, Claimed by Gix.)

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.

Skyhunter Strike Force

Flying
Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Lieutenant — As long as you control your commander, other creatures you control have melee.

Pulse Tracker

Whenever this creature attacks, each opponent loses 1 life.

Isshin, Two Heavens as One

If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Eiganjo, Seat of the Empire

{T}: Add {W}.
Channel — {2}{W}, Discard Eiganjo, Seat of the Empire: It deals 4 damage to target attacking or blocking creature. This ability costs {1} less to activate for each legendary creature you control.

Anger

Haste
As long as Anger is in your graveyard and you control a Mountain, creatures you control have haste.

Signal Pest

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Signal Pest can't be blocked except by creatures with flying or reach.

Tome of Legends

Tome of Legends enters with a page counter on it.
Whenever your commander enters or attacks, put a page counter on Tome of Legends.
{1}, {T}, Remove a page counter from Tome of Legends: Draw a card.

Mishra, Claimed by Gix

Whenever you attack, each opponent loses X life and you gain X life, where X is the number of attacking creatures. If Mishra, Claimed by Gix and a creature named Phyrexian Dragon Engine are attacking, and you both own and control them, exile them, then meld them into Mishra, Lost to Phyrexia. It enters tapped and attacking.

Caesar, Legion's Emperor

Whenever you attack, you may sacrifice another creature. When you do, choose two —
• Create two 1/1 red and white Soldier creature tokens with haste that are tapped and attacking.
• You draw a card and you lose 1 life.
• Caesar, Legion's Emperor deals damage equal to the number of creature tokens you control to target opponent.

Laelia, the Blade Reforged

Haste
Whenever Laelia, the Blade Reforged attacks, exile the top card of your library. You may play that card this turn.
Whenever one or more cards are put into exile from your library and/or your graveyard, put a +1/+1 counter on Laelia.

Serra Ascendant

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
As long as you have 30 or more life, Serra Ascendant gets +5/+5 and has flying.

Rabble Rousing

Hideaway 5 (When this enchantment enters, look at the top five cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Whenever you attack with one or more creatures, create that many 1/1 green and white Citizen creature tokens. Then if you control ten or more creatures, you may play the exiled card without paying its mana cost.

Takenuma, Abandoned Mire

{T}: Add {B}.
Channel — {3}{B}, Discard Takenuma, Abandoned Mire: Mill three cards, then return a creature or planeswalker card from your graveyard to your hand. This ability costs {1} less to activate for each legendary creature you control.

Brutal Hordechief

Whenever a creature you control attacks, defending player loses 1 life and you gain 1 life.
{3}{R/W}{R/W}: Creatures your opponents control block this turn if able, and you choose how those creatures block.

Sokenzan, Crucible of Defiance

{T}: Add {R}.
Channel — {3}{R}, Discard Sokenzan, Crucible of Defiance: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Curse of Opulence

Enchant player
Whenever enchanted player is attacked, create a Gold token. Each opponent attacking that player does the same. (A Gold token is an artifact with "Sacrifice this artifact: Add one mana of any color.")

Nadaar, Selfless Paladin

Vigilance
Whenever Nadaar, Selfless Paladin enters or attacks, venture into the dungeon. (Enter the first room or advance to the next room.)
Other creatures you control get +1/+1 as long as you've completed a dungeon.

Chivalric Alliance

Whenever you attack with two or more creatures, draw a card.
{2}, Discard a card: Create a 2/2 white and blue Knight creature token with vigilance.

Selfless Spirit

Flying
Sacrifice Selfless Spirit: Creatures you control gain indestructible until end of turn.

Wyrm's Crossing Patrol

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Flawless Maneuver

If you control a commander, you may cast this spell without paying its mana cost.
Creatures you control gain indestructible until end of turn.

Hanweir Garrison

Whenever Hanweir Garrison attacks, create two 1/1 red Human creature tokens that are tapped and attacking.
(Melds with Hanweir Battlements.)

Mardu Shadowspear

Whenever Mardu Shadowspear attacks, each opponent loses 1 life.
Dash {1}{B} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

Genasi Enforcers

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
{1}{R}: Creatures you control named Genasi Enforcers get +1/+0 until end of turn.

Vicious Conquistador

Whenever Vicious Conquistador attacks, each opponent loses 1 life.

Triumphant Adventurer

Deathtouch
During your turn, Triumphant Adventurer has first strike.
Whenever Triumphant Adventurer attacks, venture into the dungeon. (Enter the first room or advance to the next room.)

Hero of Bladehold

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Whenever Hero of Bladehold attacks, create two 1/1 white Soldier creature tokens that are tapped and attacking.

Skyknight Vanguard

Flying
Whenever Skyknight Vanguard attacks, create a 1/1 white Soldier creature token that's tapped and attacking.

Thornbow Archer

Whenever Thornbow Archer attacks, each opponent who doesn't control an Elf loses 1 life.

Den of the Bugbear

If you control two or more other lands, Den of the Bugbear enters tapped.
{T}: Add {R}.
{3}{R}: Until end of turn, Den of the Bugbear becomes a 3/2 red Goblin creature with "Whenever this creature attacks, create a 1/1 red Goblin creature token that's tapped and attacking." It's still a land.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Mardu Ascendancy

Whenever a nontoken creature you control attacks, create a 1/1 red Goblin creature token that's tapped and attacking.
Sacrifice Mardu Ascendancy: Creatures you control get +0/+3 until end of turn.

Adeline, Resplendent Cathar

Vigilance
Adeline, Resplendent Cathar's power is equal to the number of creatures you control.
Whenever you attack, for each opponent, create a 1/1 white Human creature token that's tapped and attacking that player or a planeswalker they control.

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.

Haazda Marshal

Whenever Haazda Marshal and at least two other creatures attack, create a 1/1 white Soldier creature token with lifelink.

Hammers of Moradin

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Whenever Hammers of Moradin attacks, for each opponent, tap up to one target creature that player controls.

Anim Pakal, Thousandth Moon

Whenever you attack with one or more non-Gnome creatures, put a +1/+1 counter on Anim Pakal, then create X 1/1 colorless Gnome artifact creature tokens that are tapped and attacking, where X is the number of +1/+1 counters on Anim Pakal.

Squee, Dubious Monarch

Haste
Whenever Squee, Dubious Monarch attacks, create a 1/1 red Goblin creature token that's tapped and attacking.
You may cast Squee, Dubious Monarch from your graveyard by paying {3}{R} and exiling four other cards from your graveyard rather than paying its mana cost.

Twilight Prophet

Flying
Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
At the beginning of your upkeep, if you have the city's blessing, reveal the top card of your library and put it into your hand. Each opponent loses X life and you gain X life, where X is that card's mana value.

Battle Angels of Tyr

Flying, myriad
Whenever Battle Angels of Tyr deals combat damage to a player, draw a card if that player has more cards in hand than each other player. Then you create a Treasure token if that player controls more lands than each other player. Then you gain 3 life if that player has more life than each other player.

General's Enforcer

Legendary Humans you control have indestructible.
{2}{W}{B}: Exile target card from a graveyard. If it was a creature card, create a 1/1 white Human Soldier creature token.

Luxury Suite

Luxury Suite enters tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Loyal Apprentice

Haste
Lieutenant — At the beginning of combat on your turn, if you control your commander, create a 1/1 colorless Thopter artifact creature token with flying. That token gains haste until end of turn.

Glimmer Lens

For Mirrodin! (When this Equipment enters, create a 2/2 red Rebel creature token, then attach this to it.)
Whenever equipped creature and at least one other creature attack, draw a card.
Equip {1}{W}

Reflection of Kiki-Jiki

{1}, {T}: Create a token that's a copy of another target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Fable of the Mirror-Breaker

(As this Saga enters and after your draw step, add a lore counter.)
I — Create a 2/2 red Goblin Shaman creature token with "Whenever this creature attacks, create a Treasure token."
II — You may discard up to two cards. If you do, draw that many cards.
III — Exile this Saga, then return it to the battlefield transformed under your control.