ImageOptim decreases the file size of PNG, JPEG, and GIF images, even those "Saved for Web". It combines OptiPNG, PNGCrush, AdvanceComp, PNGOUT, Jpegoptim + Jpegtran, and Gifsicle for the best possible optimization.
The gzip Recovery Toolkit attempts to automate the recovery of data from corrupted gzip files (including tarballs) through a program called gzrecover. This package is still very experimental at this point.