Tome bound in human/elf/monster skin.
A bunch of scrolls tied together.
Wind chimes that whisper spells into the mind of the mage when exposed to a breeze at midnight.
A talking skull that teaches spells.
Bone discs with spells carved into them made into a necklace.
A staff with spells engraved on it.
A flute that teaches spells to mages who play songs on it.
Rune stones that teach spells to mages who toss them onto a silk cloth.
An animal familiar that never forgets spells and can teach them to a mage.
A tree that reveals spells in the patterns of its leaves.
Metal discs that have spells engraved into them.
A painting with spells hidden within the obvious scene.