GNU Midnight Commander is a visual file manager, licensed under GNU General Public License and therefore qualifies as Free Software. Its a feature rich full-screen text mode application that allows you to copy, move and delete files and whole directory trees, search for files...
ranger is a file manager with VI key bindings. It provides a minimalistic and nice curses interface with a view on the directory hierarchy. The secondary task of ranger is to psychically guess which program you want to use for opening particular files.
noice, a blazing-fast lightweight terminal file browser with easy keyboard shortcuts for navigation, opening files and running tasks. noice is developed considering terminal based systems. There is no config file and mime associations are hard-coded.
xplr is a terminal UI based file explorer that aims to increase our terminal productivity by being a flexible, interactive orchestrator for the ever growing awesome command-line utilities that work with the file-system.