Here is a link to a company that offers quite a range of different pinion gears.
You can order just about any shaft size with any mod you would like. I think is even more options if you search they website a little more. I deal with this company for work, they supply products for stamping dies, molds, and all kind of other cool stuff.
https://fa.misumiusa.com/gwos/catalo...D1=spur%20gear