It might have happened to you - or not, if you are an amazing royal watcher or you just do not care that much - to stumble into a "Prince Philippe did this..." and if you have no mention of the City/Country of action, you don't know exactly who it is. In Italy, France, Germany, The Netherlands, the name "Philip" was massively used as a regal name, such as George, Edward, John, Carl, Albert and so on. The major difference resides in the spelling according to the country. But if you read Spanish newspapers, you might have noticed that they "translate" names. No Queen Elizabeth II there, they call her "Isabel II". Yeah...
So, back at the Philips! First, top right, Prince Philip, Duke of Edinburgh, the consort of Queen Elisabeth before-mentioned. Bottom right, Felipe, the Prince of Asturias, heir apparent to the Spanish throne. Bottom left, Prince Philippe, the Duke of Brabant, future King of the Belgians. And top left, he is not really (just a) Philip, but Carl Philip, brother of Crown Princess Victoria of Sweden and always a good reason to fit in a montage.
Second, from non-reigning houses, we have on top left Prince Philippos of Greece and Denmark, son of former King Constantine and Queen Anne-Marie of Greece. Top right, Philipp, prince of Hohenlohe-Langenburg, bottom right Prince Filip of Yugoslavia and bottom left, Philipp, Prince of Hesse.
Hope this helped a bit!