One of the leaders is Stac Electronics which has released a data compression program called STACKER.
Stac Electronics has recently released version 2.0, which claims to improve on its predecessor by adding some of the following features: smaller RAM memory requirement (26 k) for resident device driver; improved installation and support for novice users through Command Assistant and Optimizer programs; support for removable media such as Bernoulli disks or removable Syquest cartridges and even floppy disks; a full screen text editor (SEDIT) and other utilities.