Attack Trigger

Permanents whose abilities trigger on attack declaration, keying off wording such as "whenever this creature attacks", "whenever a creature you control attacks", or "whenever you attack with one or more creatures". Hellrider pings each attacker's controller, Aurelia, the Warleader grants an extra combat phase off her own attack, Goblin Rabblemaster grows per Goblin attacking, and Adeline, Resplendent Cathar spawns tokens when you attack. Isshin, Two Heavens as One doubles these same attack triggers. This covers the declare-attackers step specifically, not combat damage payoffs that read "whenever this deals combat damage" or static haste-granters that simply let creatures swing.