Install The Dropbox Desktop App ●

For Mac users, Dropbox lives in the Finder sidebar. You will also see a Dropbox icon in the Menu Bar at the top of your screen. Note that macOS may require you to "Enable Accessibility" in System Settings to allow Dropbox to show file sync icons (green checkmarks) over your folders. Linux Users

This effectively solves the problem of having a small hard drive while needing access to a massive library of files. install the dropbox desktop app