4Pane is a four pane detailed-list file manager for Linux. It is designed to be fully-featured without bloat, and aims for speed rather than visual effects. In addition to standard file manager things, it offers multiple undo and redo of most operations (including deletions), archive management including 'virtual browsing' inside archives, multiple renaming/duplication of files, a terminal emulator, and user-defined tools.
Javeau is a small tool meant to provide an easy way to create and use encrypted directories, using strong cryptography and a simple interface. It works under Java 6. Data stored in these folders are encrypted and safe (using 256 bit encryption); they can be accessed only by the user (by providing the password used to create the folder), and their integrity is checked to prevent data tampering. The application sports a convenient file-manager-like interface, is very fast and small, and is completely cross-platform: you can access your encrypted storage everywhere you can run a Java 6 VM.
Envoy is an "open and display things" library. It provides an interface for storing file associations and launching files based on those associations. This comes with a wrapper program to enable desktop users to benefit from the file associations without developers adding explicit support. It also supports opening any URI transparently, as long as the corresponding protocol support exists: applications that want simple read (and write, depending on the protocol) access to files, wherever they are, can use the envoy API to do so.
DeforaOS Browser is a file browser for the DeforaOS desktop. It depends only on GTK+ 2 and the DeforaOS System and Desktop libraries. It supports browsing with multiple views, MIME type application association, and file manipulation. It also features a program to display file icons on the desktop, which is useful with window managers like WindowMaker or Fluxbox.
DirSynch is a bidirectional directory synchronizing software. It helps you to discover the status of each file in both directories: if it's only in one of them, if it's newer in one than in the other, or if they are simply equal. After letting you to choose which files do you want to synchronize, it performs the right operations to make both directories equal (or not, if you want it different). The program can create a backup of the files before overwriting them.