If "trapped" means physically confined:
* Free
* Released
* Unbound
* Escaped
If "trapped" means emotionally or mentally restricted:
* Liberated
* Empowered
* Freed
* Unburdened
If "trapped" means in a difficult situation:
* Rescued
* Saved
* Delivered
* Exonerated
To choose the best antonym, consider the specific situation where "trapped" is being used.