Free version of Balancer Polygon reduction

Atangeo Balancer is a tool that puts your 3D polygonal models in balance. With Balancer you can
quickly and easily find your perfect balance between visual appearance and the number of polygons; optimize your models even further for best visualization performance depending on your rendering method.

Limited in amount of polygons in the free version (which actually defeats its purpose, so you might need the full version to do real optimizations).

Check the Atangeo website for details.