Enrolled into the JSS via DEP? An advanced computer search where "Enrollment Method: PreStage enrollment" is not "(blank)" should do the trick.

Otherwise if you just want to see all of the devices that are currently tied to a DEP token, head over the the JSS settings > Global Management > Device Enrollment Program. Select the account/token you want to look at, click on "Devices" at the top and you should be able to search through anything that's tied to that token.