Looking for template for bulk upload

Looking for csv or excel templates for bulk upload. Need to create one for a b2b software with a few dev challenges to consider

1. Some fields has limited options (50+) for users to selected from,
2. Can't listed them all in the form Can't use hyperlink to show all the options (security issue)

3. The options might change depending on the country that users are in

Let me know if you have experience similar challenges while creating a template But just looking for bulk upload in general...