AVFS is a system, which enables all programs to look inside gzip, tar, zip, etc. files or view remote (ftp, http, dav, etc.) files, without recompiling the programs.
Sort files and pack them into partitions
Fpart is a tool that helps you sort file trees and pack them into bags (called "partitions"). It is developped in C and available under the BSD license. It splits a list of directories and file trees into a certain number of partitions, trying to produce partitions with the same size and number of files. It can also produce partitions with a given number of files or a limited size. Once generated, partitions are either printed as file lists to stdout (default) or to files. Those lists can then be used by third party programs. Fpart also includes a live mode, which allows it to crawl very large filesystems and produce partitions in live. Hooks are available to act on those partitions (e.g. immediatly start a transfer using rsync(1)) without having to wait for the filesystem traversal job to be finished. Used this way, fpart can be seen as a powerful data migration tool.
stegfs is a steganographic file system in userspace. It uses the FUSE module which allows it to be incorporated into more than just the Linux Kernel, i.e. it's also known to work in FreeBSD :) For more details visit: https://albinoloverats.net/projects/stegfs
Gfarm file system is a network shared file system that supports scalable I/O performance in distributed environment. It can federate local disks of network-connected PCs and compute nodes in several clusters.
The NTFS-3G driver is a safe read/write NTFS driver for Linux, Mac OS X, OpenSolaris, FreeBSD, NetBSD, QNX, Windows and Haiku, providing fast and POSIX handling of the Windows XP, Windows Server 2003, Windows 2000, Windows Vista and Windows 7 file system