Credit cards - global use

An interesting question and I don't know the answer. We only use the major ones globally and have never had anyone complain or ask for others. I think, between them, they have most of the global market covered. You also have to factor in the extra cost/hassle in supporting other more niche cards. 

I think the bigger factor is not *which cards* to support when looking global but *which payment methods* to support. Germany is well known in Europe, for example, for not being big into credit card payments online (lots more direct debit and payment on delivery). Whilst I imagine if you were selling in Africa you might want to look more at mobile payments. Elsewhere the like of PayPal are very dominant.