You Seem Somewhat Familiar

Trigger You succeed or critically succeed at a Recall Knowledge check about a creature.

You fought hundreds of foes in your various past lives, and now and then, something about a new opponent tugs at your memory, almost as if you defeated their grandparent long ago. You get a +2 circumstance bonus to your next attack roll, damage roll, or saving throw against this creature. You only receive this bonus once per creature.