“ <br />
The spirit of a creature trapped in amber cannot escape to it's afterlife / next incarnation / whatever.
Such trapped spirits can be contacted by those who know the right rituals and magical power derived from them typically the power to control one individual of that species.
Can by quite powerful if the creature is a colony insect (ant, bee, wasp, etc) simply control the queen and you command the whole colony.”
“ The spellbook of a long dead wizard that has gained the ability to read itself and cast spells from itself. If could be amazingly powerful as an ally, or use its magic to manipulate and rule a kingdom.”
“ Pirates' many bejeweled rings and piercings actually had a practical purpose - when the pirate or sailor died, the rings could be taken off as payment for a proper burial, saving him from a watery grave. This could be tied into regional culture, or made into a quest (The Pirate's Lost Rings, etc.). Also gives treasure-seeking divers another thing to look for besides crusty old chests.”