The Croats created the powerful Dubrovnik Republic that competed with the Venetians. Could be civ focused on navy and trade. The Croats were presented very nicely in the mod Tomislav campaign.
Romanians (Wallachians, Moldovans and Transylvanians) were divided into three principalities that were very important in the history of Europe. They were for many years the bulwark of Europe. Besides, they already have their own campaigns in this game, even though they aren’t - a paradox, right?
Sorry for the typos:
Punjabis
Mississippian
Mamluk
Lots of people want to see the Venetians.