Safe to delete the workshop folder in Steamapps?
The workshop folder holds content from Steam Workshop - mods and other in-game content that you've downloaded for your games. Just deleting the folder won't solve your problems, because Steam will attempt to re-synchronize your files with your Workshop subscriptions.
If you want to clear out Workshop items to free up space on your computer, you'll want to locate them in the respective games' Workshop pages and choose "Unsubscribe".