I will try to get as many as possible. This is the first part.
Africa :
OK, remember that big uncolonised Africa map that keeps getting bandied around? Even excluding the unsustainable S African countries, that's still around 125.
Western Europe (minimal numbers)
The British Isles can support 10 countries (Faroes, South Scotland, North Scotland, Ireland, North Ireland, Mann, England, Wales, Channel Islands, London)
Iberia can support 8 countries (Spain, Portugal, Euskalia, Catalonia, Balearics, Galicia, Madeira, Azores)
France can support 8 countries (France, Brittany, Alsace, Corsica, Andorra, Monaco, Savoy)
Low Countries can support 5 (Netherlands, Flanders, Brussels, Wallonia, Luxembourg)
Greater Scandinavia can support 10 (Denmark, Iceland, Norway, Sweden, Finland, Sapmi, Karelia, Bornholm, Gotland, Aland)
Greater Germany can support 15 (Brandenburg, Saxony, Austria, Bavaria, Baden, Wurttemberg, Hannover, Rhineland, Hesse, Switzerland, Romandy, Schleswig, Holstein, Lichtenstein, Hamburg)
Italy can support 9 (Piedmont, Grand Tuscany, Venice, Papal States, San Marino, Napoli, Sicily, Sardinia, Malta)
rest coming later