I print gears in ABS, but pla or PETG would also work fine. As important (or more important) is the orientation in which it is printed. In a nutshell, you don't want layer lines parallel to the load path or the load can split teeth off. Print flat and at a high infill and no worries other than possible warping when printing.
I'd recommend searching 3d sites like "thingiverse" for change gear STL files. If you find something that works for tooth count, changing the center bore to match your smithy is a doodle on a site like "tinkercad" or similar....