S3QL is a file system that stores all its data online. It supports Amazon S3, Google Storage, and OpenStack and effectively provides you with a hard disk of dynamic, infinite capacity that can be accessed from any computer with Internet access. S3QL provides a standard, full featured Unix file system that is conceptually indistinguishable from any local file system. Additional features include compression, encryption, data de-duplication, immutable trees, and snapshotting, which make it especially suitable for online backup and archiving. The design favors simplicity and elegance over performance and feature-creep. Care has been taken to make the source code as readable and serviceable as possible. Solid error detection, error handling, and extensive automated test cases are provided.
OzVM (Virtual Machine Project) is a simple, lightweight, secure virtual machine. The current target application of OzVM is OzStream, which allows platform independent self-decoding of data. The vision of OzStream is to make any and all compressed media self-extracting. OzStream abstracts compressed media from client applications, providing new freedom for users, developers, and compression techniques.
Shoelacer attempts to generate a pair of small C functions that compress or decompress a set of data (primarily short strings) presented to it, and possibly other data of that kind. The data it is given may consist of entries of just a few bytes or longer. Its goal is to be reasonably fast with a tiny memory overhead. Compression performance is not so much the goal, although it certainly isn't ignored.
pngcrush is an excellent batch-mode compression utility for PNG images. Depending on the application that created the original PNGs, it can improve the file size anywhere from a few percent to 40% or more (completely losslessly). The utility also allows specified PNG chunks (e.g. text comments) to be inserted or deleted, and it can fix incorrect gamma info written by Photoshop 5.0 as well as the erroneous iCCP chunk written by Photoshop 5.5.
xz is a data compression program using the LZMA algorithm and a similar user interface to gzip. Typically it compresses both tighter and faster than bzip2, and decompresses nearly as fast as gzip. The .xz file format includes headers and checksums, and also includes data filters (LZMA2) that can increase compression further.
LRZIP is a compression program and library that can achieve very high compression ratios and speed when used with large files using unlimited sized compression windows. It uses the combined compression algorithms of zpaq and lzma for maximum compression, lzo for maximum speed, and the long range redundancy reduction of rzip. It is designed to scale with increases with RAM size, improving compression further. A choice of either size or speed optimizations allows for either better compression than even lzma can provide, or better speed than gzip, but with bzip2 sized compression levels. It also has high grade password protected encryption and full STDIN/STDOUT support.
excat is a simple tool that auto-detectd (potentially nested) compressed file formats and decompresses any combination of them using libarchive, thus unifying zcat, bzcat, lzcat, xzcat, etc. in a single (static, if you need it) binary. It may act as a drop-in replacement for any *cat.
lxz aims to create xz-compatible compressed files, utilizing multiple threads and liblzma. It was forked from lbzip2-0.23 and inherited the same internal structure. It supports compression only (basic features), and will lose its raison d'etre as soon as xz itself gets multithreading support.