Rhox Veteran

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Whenever Rhox Veteran attacks, tap target creature an opponent controls.

Syr Alin, the Lion's Claw

First strike (This creature deals combat damage before creatures without first strike.)
Whenever Syr Alin attacks, other creatures you control get +1/+1 until end of turn.

Drana, Liberator of Malakir

Flying, first strike
Whenever Drana, Liberator of Malakir deals combat damage to a player, put a +1/+1 counter on each attacking creature you control.

Patron of the Akki

Goblin offering (You may cast this spell any time you could cast an instant by sacrificing a Goblin and paying the difference in mana costs between this and the sacrificed Goblin. Mana cost includes color.)
Whenever Patron of the Akki attacks, creatures you control get +2/+0 until end of turn.

Hero of Oxid Ridge

Haste
Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Whenever Hero of Oxid Ridge attacks, creatures with power 1 or less can't block this turn.

Glory Bearers

Whenever another creature you control attacks, it gets +0/+1 until end of turn.

Kolaghan, the Storm's Fury

Flying
Whenever a Dragon you control attacks, creatures you control get +1/+0 until end of turn.
Dash {3}{B}{R} (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.)

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.

Primaris Chaplain

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Rosarius — Whenever Primaris Chaplain attacks, it gains indestructible until end of turn.

Consul's Lieutenant

First strike
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever Consul's Lieutenant attacks, if it's renowned, other attacking creatures you control get +1/+1 until end of turn.

Loxodon Partisan

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)

Accorder Paladin

Goblin Wardriver

Martial Impetus

Enchant creature
Enchanted creature gets +1/+1 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, each other creature that's attacking one of your opponents gets +1/+1 until end of turn.

Soltari Champion

Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Soltari Champion attacks, other creatures you control get +1/+1 until end of turn.

Pianna, Nomad Captain

Whenever Pianna, Nomad Captain attacks, attacking creatures get +1/+1 until end of turn.

Honored Crop-Captain

Whenever Honored Crop-Captain attacks, other attacking creatures get +1/+0 until end of turn.

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.

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.

Fervent Charge

Whenever a creature you control attacks, it gets +2/+2 until end of turn.

Kuldotha Ringleader

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)
Kuldotha Ringleader attacks each combat if able.

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.

Tori D'Avenant, Fury Rider

Vigilance, trample
Whenever Tori D'Avenant, Fury Rider attacks, all other attacking creatures you control get +1/+1 until end of turn. Other red attacking creatures you control gain trample until end of turn. Untap each other white attacking creature you control.

Anthem of Rakdos

Whenever a creature you control attacks, it gets +2/+0 until end of turn and Anthem of Rakdos deals 1 damage to you.
Hellbent — As long as you have no cards in hand, if a source you control would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.