MUE User Extension for Joomla
MPoll Poll and Froms Component for Joomla
MCME
MAMS Article Management System for Joomla 3.x, see v1.7.x for Joomla 2.5.x
MELO External Link Organizer for Joomla 3.x
The Symfony documentation
TCPDF Library for Joomla
Securimage Library for Joomla