General:
* Dispatched
* Transmitted
* Forwarded
* Delivered
* Conducted
* Conveyed
* Communicated
* Submitted
* Emitted
More specific:
* Shipped (for goods)
* Emailed (for electronic messages)
* Texted (for text messages)
* Posted (for mail)
* Released (for prisoners)
Figurative:
* Flung
* Hurled
* Launched
* Fired
* Shot
To choose the best synonym, consider the specific meaning of "sent" in the context of your sentence.
For example, "The package was sent to the wrong address" could be replaced with "The package was shipped to the wrong address".
"He sent a message to his friend" could be replaced with "He texted his friend".