So many options - not trying to replicate any in your list
Florence/Naples
Visigoths/Vandals
Kievan Rus/Golden Horde
NW Nth American native/ SE Nth American Native (a few options for both)
South Africa/Swahili
Ostrogoth/HRE
Mughal/Khazar
Scotland/Aragon/Burgandy triple pack
A couple of the Sth American native civs
Nepal/Afghanistan
Papal States/the Arabic state containing Mecca (I'm blanking on my eu3 names now) but it would be a cool synergy.
West Indies/Cuba/Haiti triple pack
there are huge numbers of options if they are looking for them.
People really need to get this "I played Europa Universalis / Crusader Kings / Victoria and now I want every single iteration of every Civilization that there ever was" nonsense, it's just getting silly now.
From the above list:
Mughals - Already part of India in the game
Kievan Rus - Already part of Russia in the game
Golden Horde - Already part of the Mongols in the game
"the Arabic state containing Mecca" - ...really?! I mean, really?! The game already has "an Arabic state containing Mecca", it is the Arabian Civilization
Scotland - As horrifyingly done as the Celts are in this game, they are clearly intended to cover Scotland
Beyond that, why on Earth do we need more Native North American groups?! Between the Iroquois and Shoshone they are hilariously overrepresented in the grand scheme of things and adding more would be a right kick in the teeth to many of peoples around the planet and a blatant show of Americo-centrism.
Also, why have nothing minor states like Burgundy and Aragon or Germanic tribes (which are arguably covered by Germany)? Surely we should be aiming to move away from this "any European Civ'll do" rubbish.
Then South Africa? Sure, there are some "interesting" gameplay options there if institutionalised racism is your thing. Yes there is an obvious choice of leader who could get away from all of that, but it is still very recent and not something that a video game should bring up at this point in time.
As for the Holy Roman Empire, people vary from hating having it, declaring it "part of Germany" (or Austria) to demanding it's inclusion. I don't get this. Yes, the Holy Roman Empire of Civ IV was nonsense and actually Charlemange's Empire (who whilst "Holy Roman Emperor" did not rule the "Holy Roman Empire" which arguably began with Otto I). That said, in this version at least it's pretty damn clear that you can't have Germany, Austria
and the Holy Roman Empire.
We've also just about got over including Venice, who can just about differentiate themselves as a "Civ" (I still dislike them as an option, but hey), but suddenly Florence and Naples (who aren't even in as a City State).
Also, get over the Papal States, they aren't a Civilization. They are a political institution of questionable morals who manipulated people's deepest fears for profit and political gain for centuries and having them as a city state is more than enough.
In fact, of that whole list, only:
Khazars
Swahili
Afghanistan
Nepal
West Indies
Cuba
Haiti
...and of them only the Khazars and Swahili are really decent options. That said, Swahili is a bit of a sticky option in and of itself, and an Omani Civ would probably be an better option, although maybe both could work together (the name Zanzibar or Swahili could work in principal). I don't quite get the relevance between Afghanistan and Nepal though, nor Swahili, and South Africa for that matter (maybe being vaguely in the same vague region is close enough?). This is particularly confusing when there are plenty of very obvious DLC packs which could be done if that was the road they want to go down:
Khazars & Afghanistan - The Silk Road
Zanzibar & Oman - The Swahili Coast and Trade
Mali & Kongo - Africa of the middle ages
Khmer & Pagan - South East Asia of the middle ages
There'd even be:
Canada & Australia - Colonies of the Commonwealth
Argentina & Gran Colombia (or another) - Former Spanish Colonies
If you're into that kind of thing.