Seeking source of small, molded plastic gears

I am developing a product that uses a 6mm diameter .5Mod worm and worm-gear connected to a small Brushed DC motor (similar to those found in toys.)

I am having trouble sourcing the gears. On Ebay and Amazon, you can buy bags of hundreds of molded gears, and if you are lucky, in the bottom of the bag is the one gear you need.

Does anyone know of a reliable source for small molded plastic gears?

Thanks!

Dan
San Jose, CA