To correlate with alixaannencova's very interesting thread on sins, perhaps one of the 7 cardinal virtues. I'm sure it won't be nearly as much fun as the other but might be worth a whirl

:
Chastity
Temperance
Charity
Diligence
Forgiveness
Kindness
Humility
Chastity--Princess Beatrice, at least longer than many of her contemporaries. The recent bio on Princess Beatrice wrote in detail about the length Queen Victoria went to keep anything for corrupting her chaste daughter. There was to not be talk of romance, marriage and, especially, childbearing around her delicate daughter. I can also think of several princesses/archduchesses who took early vows as nuns.
Charity--Princess Mary Adelaide and Grand Duchess Elizabeth come to mind here. Mary Adelaide achieved great popularity due to her various charitable endeavors. Grand Duchess Elizabeth devoted her post-widowed life to serving the poor of Moscow. The Schleswig-Holstein princesses--Helena, Helena Victoria (Thora), Marie Louise all devoted themselves to charities throughout their lives. Marie Louise was still attending functions of her various charities until shortly before her death.
Diligence--Queen Mary comes to mind here. Certainly few royals of any era devoted themselves more towards the carrying out of their duties. Also George V who was signing documents almost up until the moment he died. He also handed out medals while laying in his field hospital bed.
Forgiveness--Again, Grand Duchess Elizabeth--granting forgiveness to the assassin of her husband.
Kindness--Queen Alexandra was renowned for the kindness she showed to almost all those who crossed her path.
Humility--Princess Helen of Romania (and Greece) suffered a good deal at her husband's hands but led a decent and retiring life (when she could've really made a press play and capitalized on the sympathy she got from many) and devoted herself to her son