I am not aware of a good resource for standard motor sizes like that. However, if you want to compare the sizes of our motors you can click on the "Compare all products in this category" link located on the main category pages of each of the motor types we carry to see a chart of those motors dimensions listed in the "Size" column. That column can be re-ordered using the up and down arrow at the top for ascending or descending dimensions. Additionally, most of our motors have a dimension diagram available on their respective product pages.
I hope you find this helpful!