qFSView is a free and open source storage visualization app for Linux. Using this you can view your system storage utilisation as a treemap charts and helps you to view which files are taking the most space in your system. It is released under GNU General Public License v2.0 license and a fork of KDE Konqueror plugin FSView. You dont need to install KDE dependencies to use this app. You can navigate each folder by clicking on a rectangle and right click to open the qFSView menu. Some of its features are colour modes, visualisation modifications and annotations for names, types, sizes.