Steam Game Removal on Different Drives

Uninstalling Steam will also remove all of your installed games (including in separate libraries), save games, and other downloadable content.

If you want to back up your games before uninstalling Steam, say for example you're reinstalling the client, you can take a copy of your library folder before you perform the uninstallation and then restore it after uninstalling the client. When you reinstall Steam you need to create a new library at the existing library location and then choose to reinstall all of the games in that library for Steam to correctly find the files.