Royal descendants of John William Friso

The royal descendants of John William Friso, Prince of Orange currently occupy all the hereditary European royal thrones, with Friso and his wife, Landgravine Marie Louise of Hesse-Kassel, being the most recent common ancestors of all the European monarchs. Due to the intermarriage of the European royal houses, many monarchs are descended from Friso in more than one way. Through history, Friso has also been the ancestor of many monarchs whose thrones no longer exist.
Albania.
Wied, Prince of Albania, the only ruler of the Principality of Albania, was descended from Friso through both children of his son. Through his grandson, William V, Prince of Orange:
Through his granddaughter, Princess Carolina of Orange-Nassau:
With the death of Wied's son, Carol Victor, the line became extinct.
Austria-Hungary.
Charles I of Austria, the last reigning Emperor of Austria and King of Hungary, was descended from Friso through his daughter's son:
Belgium.
King Philippe of Belgium is descended from Friso through both his son and his daughter's son. Through his grandson, William V, Prince of Orange:
Through his granddaughter, Princess Carolina of Orange-Nassau:
Through his daughter, Princess Amalia of Nassau-Dietz: 
Brazil.
At present, both lines that lay claim to the throne of the former Empire of Brazil, have produced claimants who are descended from Friso.
The claimant of the Vassouras branch, Prince Luiz of Orléans-Braganza, is descended from his son's daughter:
The claimant of the Petrópolis branch, Pedro Carlos of Orléans-Braganza, is also descended from his son's daughter:
Bulgaria.
Simeon II of Bulgaria, the last Bulgarian Tsar, is descended from Friso through his son's daughter and his daughter's son. Through his son, William IV, Prince of Orange:
Through his daughter, Princess Amalia of Nassau-Dietz:
Denmark.
Queen Margrethe II of Denmark is descended from Friso through both children of his son and his daughter's son in four:
France.
At present, of France's three monarchist movements, Orléanism, Legitimism and Bonapartism; all have produced claimants to the defunct French throne, who are descendants of Friso.
The Orléanist claimant, Jean, Count of Paris, is descended from Friso through his son's daughter:
The Legitimist claimant, Louis Alphonse, Duke of Anjou, is descended from Friso in two ways, once through his son's daughter, and once through his daughter's son:
The Bonapartist claimants, Charles, Prince Napoléon and his son Jean-Christophe, Prince Napoléon, are descended from Friso through his son's daughter:
Germany.
At the time of the dissolution of the German Empire in 1918, all but four Constituent States of Imperial Germany had produced reigning monarchs who were descended from Friso. The four monarchs who could not claim descent from Friso were: Joachim Ernst, Duke of Anhalt, the last ruler of the Duchy of Anhalt; Adolphus Frederick VI, Grand Duke of Mecklenburg-Strelitz, the last reigning Grand Duke of Mecklenburg-Strelitz; Alexander, Prince of Lippe, the sovereign of the Principality of Lippe; and Günther Victor, Prince of Schwarzburg. the last monarch of the unified principalities of Schwarzburg-Rudolstadt and Schwarzburg-Sondershausen.
Baden.
Frederick II, Grand Duke of Baden, the last reigning Grand Duke of Baden, a constituent of the German Empire, was descended from Friso through his daughter's son:
Frederick II had no children, so upon his death his first cousin Prince Maximilian of Baden became the pretender. Here is his lineage:
Maximilian's grandson, also named Maximilian, and the current pretender, is additionally descended from Friso through his mother's lineage:
Bavaria.
King Ludwig III of Bavaria, the last reigning Bavarian monarch, was not descended from Friso, but his son, Rupprecht, Crown Prince of Bavaria, was through Friso's son's daughter:
The Dukes of Bavaria, beginning with Rupprecht, are also the heirs to the Jacobite claim to the British thrones.
Brunswick.
Ernest Augustus, Duke of Brunswick, the last reigning Duke of Brunswick, was descended from Friso through his son's daughter:
Hesse and the Rhine.
Ernest Louis, Grand Duke of Hesse, the last reigning Grand Duke of Hesse and by Rhine, was descended from Friso through his daughter's son:
Upon Louis's death, his cousin Philipp, Landgrave of Hesse became the pretender. Even though he is not descended from Friso, he married the daughter of King Victor Emmanuel of Italy, Princess Mafalda of Savoy, a descendant of Friso's daughter's son. Therefore, their grandson, the current pretender Donatus, Landgrave of Hesse is a Friso's descendant:
Mecklenburg-Schwerin.
Frederick Francis IV, Grand Duke of Mecklenburg-Schwerin was descended from Friso through his daughter's son in two ways:
Upon Friedrich Franz's death, the line became extinct.
Oldenburg.
Frederick Augustus II, Grand Duke of Oldenburg, the last reigning Grand Duke of Oldenburg, was descended from Friso through his son's daughter:
Anton-Günther is also descended from Friso's son's daughter through his mother in two ways:
Prussia.
Wilhelm II of Germany, the last Kaiser, was not descended from Friso, but his grandson Louis Ferdinand, Prince of Prussia was descended from Friso's daughter's son in two ways:
Georg Friedrich, the current pretender, is additionally descended from Friso's daughter's son in one additional way:
Reuss-Gera.
Although the last reigning Prince Reuss-Gera, Heinrich XXVII, Prince Reuss Younger Line, was not a descendant of Friso, his son the last Hereditary Prince, was:
Reuss-Greiz.
Heinrich XXIV, Prince Reuss of Greiz, the last reigning Prince Reuss of Greiz, descended from Friso through his son's daughter:
Saxe-Coburg-Gotha.
Charles Edward, Duke of Saxe-Coburg and Gotha, the last reigning Duke of Saxe-Coburg-Gotha, was descended from Friso through his son's daughter in two ways:
Alternative pretender Andreas, Prince of Saxe-Coburg and Gotha is the son of a younger son of Charles Edward.
Saxe-Meiningen.
Bernhard III, Duke of Saxe-Meiningen, the last reigning Duke of Saxe-Meiningen, descended from Friso through his son's son:
Saxe-Weimar-Eisenach.
William Ernest, Grand Duke of Saxe-Weimar-Eisenach, the last monarch of Saxe-Weimar-Eisenach, was descended from Friso through both children of his son:
Saxony.
Frederick Augustus III of Saxony, the last reigning King of Saxony, was a descendant of Friso through his daughter's son:
Schaumburg-Lippe.
Adolf II, Prince of Schaumburg-Lippe, the last reigning Prince of Schaumburg-Lippe, was descended from Friso through his son's daughter:
Upon Adolf's death, his brother Wolrad became the pretender, his descent is shown here:
Waldeck and Pyrmont.
Friedrich, Prince of Waldeck and Pyrmont, the last reigning Prince of Waldeck and Pyrmont, was descended from Friso's son's daughter in two ways:
Württemberg.
William II of Württemberg, the last reigning King of Württemberg, was descended from Friso through his son's daughter:
Upon William's death, the royal branch of the line became extinct, and the ducal branch succeeded as pretenders, beginning with Albrecht, Duke of Württemberg, whose lineage is shown here:
The current pretender, Carl, is descended from Friso's son's daughter in one further way and also from his daughter's son in another:
Greece.
King Constantine II of Greece, the last Greek King, is descended from Friso through his son's daughter in two ways:
Queen Anne-Marie of Greece, the King's wife, is the sister of Queen Margrethe II of Denmark. See their lineage here.
Italy.
Savoy.
King Umberto II of Italy, the last Italian King, was descended from Friso through his daughter's son:
Two Sicilies.
At present, both lines that lay claim to the throne of the former Kingdom of the Two Sicilies, have produced claimants who are descended from Friso.
The claimant of the Castro branch, Prince Carlo, Duke of Castro, is descended from his son's daughter:
The claimant of the Calabria branch, Prince Pedro, Duke of Calabria, is descended from his son's daughter six ways; one way he descends from his son's daughter is:
Liechtenstein.
Hans-Adam II, Prince of Liechtenstein is descended from Friso through his daughter's son:
Luxembourg.
Henri, Grand Duke of Luxembourg is descended from Friso through his son's son in one way and his son's daughter in two:
Monaco.
Albert II, Prince of Monaco is descended from Friso through his daughter's son:
Netherlands.
King Willem-Alexander of the Netherlands is descended from Friso through his son's son in one way and his son's daughter in two:
Norway.
King Harald V of Norway is descended from Friso through his son's son in two ways and his son's daughter in one:
Portugal.
Although Manuel II of Portugal, the last King of Portugal, was not descended from Friso, his Queen consort Augusta Victoria of Hohenzollern, was. She descended from his son's daughter:
The current pretender to the Portuguese throne, Duarte Pio, Duke of Braganza, is not descended from Friso, although through his great-grandmother, Princess Adelaide of Löwenstein-Wertheim-Rosenberg, he is a descendant from William I, Count of Nassau-Dillenburg (great-great-great-grandfather of John William Friso).
Romania.
King Michael I of Romania, the last King of Romania, was descended from Friso through his son's daughter in one way and his daughter's son in two:
Male line:
Russia.
Tsar Nicholas II of Russia, the last Tsar of Russia, was descended from Friso through his daughter's son:
The current pretender status to the Russian throne is disputed, but only one line descends from Friso, also through his daughter's son:
Another line:
Spain.
King Felipe VI of Spain is descended from Friso through his son's daughter in four ways and his daughter's son in one:
Sweden.
King Carl XVI Gustaf of Sweden is descended from Friso through his son's daughter in three ways and his daughter's son in two:
United Kingdom.
Queen Elizabeth II of the United Kingdom is descended from Friso through his son's daughter:
Prince Philip, Duke of Edinburgh, the Queen's husband, was descended from Friso through his son's daughter in one way and his daughter's son in two: 
Yugoslavia.
King Peter II of Yugoslavia was descended from his daughter's son in two ways:
The current pretender's mother was a Princess of Greece as the granddaughter of King Constantine I of Greece.
Through her, the current pretender is also descended from Friso's son's daughter.