Less anachronistic Romanian flag
As much as we all love the modern Romanian tricolor, its existence is owed to the 1848 revolutions and the French revolution by extension. Events still in the far-flung future at the point when most EUV players form the country.
I’ve combined the coats of arms of Wallachia, Oltenia, Moldavia and Transylvania into a flag more in line with those of other early modern European kingdoms.
The tricolor can still be obtained should Romania become a revolutionary republic.
Perhaps I’ll update this to include variants based on which Romanian culture is primary and which are accepted, but no promises.