I recently needed to free up disk space on my 2018 Macbook pro 250gb. After running my goto for checking disk space..the amazing utility Disk Inventory X , I found that Xcode and in particular CoreSimulator was using around 26GB or 10% of my entire disk. After quick google search I ended up on Stack Overflow and ran the following command in terminal.app :
xcrun simctl delete unavailable
This gave me back 17Gb of disk space which is not unsubstantial when developing applications.