'Lrzip uses an extended version of rzip which does a first pass long distance redundancy reduction. The lrzip modifications make it scale according to memory size. [...] The unique feature of lrzip is that it tries to make the most of the available ram in your system at all times for maximum benefit. It does this by default, choosing the largest sized window possible without running out of memory.'

15% smaller than bzip, 30% smaller than gzip, and now shipped with Fedora and Ubuntu. uses LZMA2

'A parallel implementation of gzip for modern multi-processor, multi-core machines', by Mark Adler, no less