Among 3D mesh optimizing tools, Polygon Cruncher, developed by Manuel Jouglet, owner of the french company Mootools, is the most renowned program. Polygon Cruncher reduces the number of polygons of 3D objects without changing their appearance. You keep all details, materials, textures, vertex colors and normals, even at high optimization ratio. Polygon Cruncher uses an exceptional algorithm developed since more than 10 years and gives incomparable results. It is really simple to use and has been chosen by major 3D companies.
The latest version of Polygon Cruncher is 10.02 released on May 25, 2012. Polygon Cruncher exists in different version: StandAlone which includes Maya files support, plugin for 3D Photo Browser, plugin for 3DS Max / 3ds Max Design and plugin for Lightwave Modeler. A free SDK for developers, offering Polygon Cruncher optimization features through a C++ library is also available. The price for a full single licence is 129$.
Another famous mesh optimizing tool (open source) is Meshlab.
Other mesh optimizing tools are listed hereafter :