House of Hannover
So far we have...
- Christian Ludwig (1622-65) Succeeded by his younger brother
- Georg Wilhelm (1624-1705) He remained unmarried and the question of his heir was somewhat complex, but was tied up with the idea of his illegitimate daughter marrying his nephew, who became George I of England. Whether this happened or not, his heir would have been his nephew.
- Georg Ludwig (1660-1727) who in our history became George I. He was succeeded by his son...
- Georg Augustus (1683-1760) whose parents in our history were first cousins and was George II.
- Friedrich Ludwig (1707-1751) was Georg Augustus' eldest son. In our history he predeceased his father, but his son became George III.
- Georg Wilhelm Friedrich (1738-1820) was the first real "English" King of the Hanovers, and his marriage was to a German princess. At this point things might be considered tricky, because many of those *here* have a kind of doppelganger already *there*. On the other hand, that needn't be a problem. We'll see.
- Georg Augustus Friedrich (1762-1830) was the Prince Regent (i.e. George IV) *here*, but assuming for a moment he was King of Hannover, then his marriage to yet another German Princess makes sense.
- Charlotte Augustus (1796-1817) was this man's only child. Now, if Hannover does not have Salic law and/or if Charlotte Augustus outlived her father, we have the intriguing possibility that her husband became King of Hannover. He was...
- Leopold Georg Christian Friedrich (1790-1865), Prince of Saxe-Coburg-Saalfeld. In our history he became the first King of Belgium, which of course did not exist *there* but gives us an insight into what kind of monarch he might have been. See 
- Leopold Ludwig (1835-1909) was Leopold's heir, albeit by a second (and French) wife. If we simply assume that Georg Augustus Friedrich died circa 1817 or so, after his daughter's marriage, then we have the real possibility that the royal house of Belgium *here* has become the royal house of Hannover *there*. Incidently, Leopold Ludwig was a vicious, evil man. But continuing...
- Albrecht Leopold (1875-1934) was Leopold Ludwig's grandson, and a far nicer person. He was succeeded by his son.
- Leopold Philipp (1901-1983) who abdicated in 1951, under the cloud of actions taken during WWII or GW2.
- Albrecht Karl (born 1930-1993) was the eldest son of Leopold Philipp (or Leopold III of Belgium). In *our* history he died at age 63 but I don't see any reason he couldn't have lived instead, making him 78 years old at the present time, having perhaps been elected Holy Roman Emperor in 1976 when he was 36. Or perhaps his lifespan was the same as here, in which case his successor was/will/might be...
- Albrecht Felix (born 1934) the younger brother of the previous king.