pigz is the parallel implementation of gzip: the input is sliced into 128 KB blocks and spread over the cores, while the output stays a standard gzip stream. Version 2.8 dates from August 2023, and decompression remains single threaded.

lzop compresses files through the LZO library, ships under the GPL, and puts speed ahead of ratio on both sides of the job. Version 1.04 defaults to level 3 and keeps the source file, which suits backup archives.

BZip3 compresses text and source code without loss, pushes the block ceiling from 1 MiB up to 511 MiB, adds a Lempel-Ziv predictor ahead of the transform, swaps in context mixing for entropy coding, and ships six command line tools.

XZ Utils is free general purpose data compression software built on LZMA2, producing the .xz format that source packages and firmware images so often use, with a liblzma library other programs can call directly.

FreeArc is the archiver Bulat Ziganshin built around one obsession: pick the algorithm per file type, then stack every trick available. Text goes to PPMd, executables get BCJ preprocessing, solid blocks and recovery records protect the result, and AES, Twofish and Serpent can be chained. Frozen at 0.67, still unmatched as a study in compression design.

PAQ8px is a research compressor from the PAQ family that mixes dozens of prediction models to push lossless output towards the entropy limit, at the cost of time and memory.

LZ4 is an open-source lossless compression library built for paths where data cannot wait: more than 500 MB/s of compression per core, decompression in the gigabytes per second per core, which usually hits memory bandwidth as the ceiling. Ratio is traded away for latency low enough to sit inside real-time traffic, and version 1.10.0 turns multithreading into a supported feature.

A parallel, indexed compressor built on the xz format. It uses every core on the machine by default, keeps an index so a single file can be pulled out of a large archive without unpacking the rest, and handles tar files in one step. Open source under a BSD licence.

GNU tar packs files and directories into one archive while keeping structure, permissions and timestamps, and leaves compression to gzip, xz or zstd.

GNU tar turns a tree of files into one container and hands the shrinking to gzip, xz or zstd, so creating, extracting, listing and pulling out a single file each take one short command.