Some old ones:
Queen Friedrike and the Infantas Elena and Cristina
CG with his grandfather
Princess Ingeborg with her Belgian grandchildren (the children of her daughter Astrid) Albert II, Baudouin, and Josephine Charlotte
Christian IV and four of his grandchildren: Alexandra and Constantine of Greece, and Victoria and Maude of Wales
Charles with Grandpa George VI
Queen Mary with Prince William and Prince Richard of Gloucester
Rainier with Princess Alexandra
Prince Philip's grandmother Princess Victoria of Hesse and one of her many great grandchildren Prince Ludwig of Hesse
Queen Juliana with Queen-mum Emma
Queen Victoria and Ena (Queen Victoria Eugenie of Spain)
Queen Mary with Princess Elizabeth