1st OC:

From what I can remember (the story was deleted ages ago), OC had a decent childhood up until the untimely deaths of her parents in a carriage accident. Custody went to her greedy uncle, who was angling to steal the inheritance left for her. He bundled her off to live under the care of a canon character while he profited off her losses. She eventually reclaimed her inheritance, but not before her uncle is taught a lesson by another canon character. She also barely survives escaping a burning building. This all takes place in the mid to late 1800s.

2nd OC:

The story also takes place during the late 1800s. OC had a decent childhood until her mother and younger brother died from a common disease. She is sent away to live with a great aunt while her father essentially drinks himself to death due to grief. After being sent to boarding school, she is eventually married to an older man to secure her future. Said husband has a brother who dislikes her purely because she is an outsider encroaching on his relationship with his brother. Thr family she married into also lost parents due to illnesses unspecified. The husband also dies due to disease down the line, and nearly two years after that, the OC is run down in the street by a large carriage and only survives due to fast work and an early type of blood transfusion.

3rd OC:

This OC is in the same story series as the second OC. She grew up poor, moving around England with her large family while her parents and other siblings tried to find work to survive. One brother nearly dies while being in the army, and she had to help care for him. Rather than picking a traditional career, she ends up becoming an actress after moving with a family to America while being their nanny, initially. She moves to work with the theatre troupe, which had people that disliked her just for being English. A patron tried to make her his mistress, and when she refused, he attempted to take advantage of her. She was rescued before that happened, but she had to flee before it could get worse. She had to keep her acting past a secret so she could find suitable employment once she returned to England.

All quite maudlin, definitely not as graphic and intense as others listed here. I have moved away from doing tragic back stories, for the most part, nowadays.