rrd-fixpeaks removes errant "peaks" in RRD data. It requires rrdtool.
statsd-go is a reimplementation of statsd in Go (forked from gographite) with Ganglia submission support.
statsd-c is a reimplementation of Etsy's famous/infamous "statsd" in C.
rrd-merge merges RRD (round robin database) files together, including the files used by Ganglia, Cacti, and other rrdtool-based software.
An image batch converter and resizer with advanced features.
A tool that makes graphical and top reports from the Squid proxy access log.