I just cloned a project into Xcode and am trying to run it in the simulator. However, my only option is iOS Device. This is unique to this project only and I don\'t know how to
For what it's worth, my issue seemed to be that I had two different versions of xcode running at the same time (8.2 and 9.2). Xcode might grab a list of simulators and, as resources, lock them up and make them unavailable for other versions of xcode to avoid issues. I killed (cmd+q) both xcode instances, restarted the one I needed at that point, and then the simulators showed up again.
Hope this helps anyone else, since it took me quite a bit of time to figure this one out, since it was an 'on and off' kind of issue.