FreeArc

FreeArc is an open-source file compression utility which is popular for its highest compression levels. FreeArc uses LZMA, PPMD, TrueAudio, Tornado and GRzip algorithms with automatic switching by file type, and also uses set of filters. FreeArc works 2-5 times faster than best programs in each compression class while retaining the same compression ratio; from technical grounds, it's superior to any existing practical compressor. You can use any external program as compressor or filter as easy as internal ones, with Precomp, ECM, CCM(x), PPMonstr, Durilca, LPAQ, UDA and PAQ are already preconfigured in arc.ini as shipped