Aurelia, the Law Above

Flying, vigilance, haste
Whenever a player attacks with three or more creatures, you draw a card.
Whenever a player attacks with five or more creatures, Aurelia deals 3 damage to each of your opponents and you gain 3 life.

Tori D'Avenant, Fury Rider

Vigilance, trample
Whenever Tori D'Avenant 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.

Paladin Elizabeth Taggerdy

Battalion — Whenever Paladin Elizabeth Taggerdy and at least two other creatures attack, draw a card, then you may put a creature card with mana value X or less from your hand onto the battlefield tapped and attacking, where X is Paladin Elizabeth Taggerdy's power.

Aurelia, the Warleader

Flying, vigilance, haste
Whenever Aurelia attacks for the first time each turn, untap all creatures you control. After this phase, there is an additional combat phase.

Gisela, Blade of Goldnight

Flying, first strike
If a source would deal damage to an opponent or a permanent an opponent controls, that source deals double that damage to that player or permanent instead.
If a source would deal damage to you or a permanent you control, prevent half that damage, rounded up.

Lightning, Army of One

First strike, trample, lifelink
Stagger — Whenever Lightning deals combat damage to a player, until your next turn, if a source would deal damage to that player or a permanent that player controls, it deals double that damage instead.

Sephiroth, Fallen Hero

Jenova Cells — Whenever Sephiroth attacks, you may put a cell counter on target creature. Until end of turn, each modified creature you control has base power and toughness 7/5. (Equipment, Auras you control, and counters are modifications.)
The Reunion — {3}, Sacrifice a modified creature: Return this card from your graveyard to the battlefield tapped.

Agrus Kos, Wojek Veteran

Whenever Agrus Kos attacks, attacking red creatures get +2/+0 and attacking white creatures get +0/+2 until end of turn.