Apple Configurator stores IPSW files and backups locally, which can consume a lot of space on your machine's SSD.
The IPSW system file cache:
~/Library/Group Containers/K36BKF7T3D.group.com.apple.configurator/Library/Caches
Backups from MacOS:
~/Library/Containers/com.apple.configurator.xpc.DeviceService