How to remove Garage band Instruments and lessons from taking up storage on iMac

. I looked everywhere in the library for loops, everything cannot find this anywhere to delete it...

There are two libraries where you need to look, the Library folder at the top level of your system drive and the User Library folder at the top level of your User Home folder.

Did you look in both Library folders?

• The sounds, Learn to Play and other items should be in
  • System install library: /Library/Application Support/GarageBand/
  • User Library: ~/Library/Application Support/GarageBand/
• The loops should be in
  • System install library: /Library/Audio/
  • User Library: ~/Library/Audio/

Your user library folder may still be hidden. You can open these folders by pasting the path into the Finder's Go menu:

Finder > Go > Go to Folder ⇧⌘G

I had this same problem. I called apple for support. The tech lady, she had me reinstalled garage band, then went to the storage & there's now an option to get rid of the annoying 2.66GB of files in music & creation. Then I just uninstalled garage band. Hope this helps.