Is there available an add-on Task-bar indicator to show mounted usb devices and enable safe removal?
To expand on Schyken's answer you can find all of the wingpanel indicators made by the elementary team on the Github here: https://github.com/elementary?utf8=%E2%9C%93&q=wingpanel&type=&language=.
Perhaps you can suggest an indicator in an issue or alternatively just use GNOME which has a Removable Drive Menu shell extension.