I am deleting some folders and files to make more space on my drive. I know that in path:
~/Library/Developer/CoreSimulator/Devices/
There are
Sometimes Xcode likes to double up on its simulators.
Usually the fix for me has always been to just delete them all. Deleting them is harmless as you can always download them again later.
Xcode > Preferences > Downloads
Just remember that if you have any old simulators in there (iOS 8.0-) you won't be able to download them again through Xcode.