In my big TL (late 1390s POD) the stereotypes in the latter half of the 20th century are :
- Muscovites are perfiduous goodfornothing creepy messianistic fascist thugs, what do you mean the war has been over for decades ?
- Novgorodians are highly wealthy and supportive of research and new tech development, but they look down on all other Russian nations and ape everything Scandinavian, Baltic and western
- northern Germans, Danes, the Irish and Serbs are dirty commies ("In Ochsolist Brandenburg, history alternates jokes about you !"), the Irish and Serbs are both commies and religious fundies
- Germans as a whole are a merry and resourceful bunch, but also loud, foul-mouthed, slovenly and ill-disciplined
- Anglo-Dutch is teh awsum language of commerce, science and nerds
- the French are heroic in battle, but notoriously conservative in values, including a heavy dislike for state-sponsored welfare
- Newkalmarites* and Nieuw Zealanders** are easy-going and friendly, but overtly Europe-loathing and cocksure about their own importance on the world scene
- the Habsburg-ruled Alpine countries (including a Switzerland with the "unchangeable borders" cliché torn to pieces) are fairly wealthy, but also extremely boring with their quaint provincial tea-sipping atmosphere
- the Japanese*** are a nation of skilled marksmen and as gun-lovin' as OTL US rednecks (samurai and bushi with matchlocks and flintlocks are the norm in pop-cultural depictions of Japanese feudalism)
- Vallachians and Moldovans are crazy nationalistic terrorists, in cahoots with the equally anti-Croat and anti-Hungarian alliance of Albanians and Serbs
- the Italians make cool gadgets (particularly military and aerospace tech) and come up with slang and memes even cooler than the Anglo-Dutch ones (Italian is pretty synonymous with "hip" and "trendy" ITTL - in a youthful kind of way)
* vaguely some place Canadian... or north-US-ian ?

** ah, yes, the former Dutch colony in North America, now one of the richest republics in the world

*** a republic since the late 19th century (when an anti-monarchist revolution took place, plus there was no emperor revival like in the Meiji period)
IMPORTANT NOTE : You can use these for inspiration, just don't steal any of my ideas.