Augusta Victoria of Schleswig-Holstein was a minor princess distantly related to Queen Victoria, and married a distant relative, the last Kaiser of Germany.
Victoria, Princess Royal, the eldest daughter of Queen Victoria, wasn't just a regular Empress. She was a Crown Princess with liberal views she wasn't afraid to share.
Marie-Adélaïde of Luxembourg isn't a name you might have heard. This woman did a ton of stuff though — including pretty much running away from her own country.
Margherita of Savoy was the first woman to hold the title of Queen of Italy. She's also my favorite historical figure because she's just amazing.
Princess Mafalda of Savoy did nothing except exist, which made Hitler pretty angry. She met a terrible end in a terrible concentration camp.