Ability for adding a spell to a class list?

[Weirdo]

I half-remember seeing an ability that allowed a character to add a spell to their class list from another class list of the same type (arcane or divine). For example, a Druid could add a Cleric or Inquisitor spell to their list, and a Magus could add a Bard spell.

Can anyone tell me what this ability is, or whether it exists?

[Nebraskaslim]

That would be mystic past life. It is an alternate racial trait for Samsaran.

[Weirdo]

Thanks.

[deuxhero]

That's not the only one.

Improved Eldritch Heritage: Arcane gives any spontaneous caster Sorcerer spells
Pathfinder Savant lets you pick ANY spell and add it to your list at one level higher.
Someplace Arcanist of Paths of Prestige gives lots of out of list stuff. Other things in the book may potentially do so as well.
Cracked Orange Prism adds a cantrip to your spells known or prepared with no regard for list
Honorable mention to Razmiran Priest Sorcerer archetype, who can use spell slots to avoid using up a scroll or wand, and some alchemist discovery, which lets you blow "spell" slots to avoid using up a potion.

This is one thing PF is surprisingly more open on than 3.5 was.