Garageband missing library sounds and can't use inbuilt piano keyboard

Hello jeremy_db, 

Welcome to the Apple Support Communities. 

If you are noticing that some instruments are missing from GarageBand, you can try to install them again or restore from a backup. Check the following Apple Support articles for instructions: 

• Restore items backed up with Time Machine on Mac
• Get more sounds and loops for GarageBand on Mac
• Use Audio Units plug-ins with GarageBand on Mac

If there seems to be a larger issue when opening or using GarageBand, you can also try these recommended troubleshooting steps: If GarageBand isn't working on your Mac.

Please reply back here for more help, or contact Apple Support directly. 

All the best! 

It is a bit confusing. I am seeing only the same for patches, when I have an existing audio track selected. But when I create a new track, all installed instruments are visible, and there is a new drop-down menu, to select all instruments:

So, try to create a new track, to see more instruments.

And use the scrollbar at the bottom of the panel to get to the list of all instrument categories.

The scrollbar may be hidden and only appear, when you try to scroll.