[Edit 17/06/2021 - Removed table for browser compatibility & added the pic]
For horror/fantasy settings, 18 Dark Secrets as character background and possible adventure hooks; I'm sure you've got the know-how and imagination to make-up any rules and mechanics you may need.
Black Ichor as at https://dysonlogos.blog/2018/08/06/further-delves-for-the-black-ichor/ or whatever suits you.
1st d6 (1 to 2) 2nd d6:
- You are of non-human ancestry; it does not show, but you feel it growing stronger with each passing year.
- You have taken the Black Ichor and are driven to seek it out in the underworld until such time as you find a cure.
- You are a survivor of a catastrophic adventure and only you (maybe a few others) know what really happened and what you had to do to survive.
- You carry a dreadful sickness that does not harm you, but consumes those around you.
- You are property; you do not wish to be claimed. The one who has a claim over you does not have your interest at heart.
- You have a double bent on disrupting/ usurping your life; it is better than you in every way, and seems to be more convincing as you than you are.
1st d6 (3 to 4) 2nd d6:
- You once stole an item of great worth; you no longer have it, but that means nothing to those you took it from.
- You were once a member of a particular faith, and they will not allow their sheep to stray.
- You are running from colossal debts owed to the worst kinds of creditors.
- You are held responsible for the death of a figure of considerable significance.
- You robbed the wrong tomb or temple, and have been marked for retribution.
- You are unwilling host to a parasite/ symbiote, spiritual or material.
1st d6 (5 to 6) 2nd d6:
- You descend from an ancient and accursed line; you struggle to hide your identity and to avoid your supposedly inescapable fate.
- You previously followed a reviled profession/creed/leader, and you can expect neither sympathy or understanding if it was to become known.
- An entity or organisation has capriciously taken a dislike to you, and will go to great lengths to discomfort you and those around you.
- Sometimes you lose hours, days, weeks, and have no recollection of what occurred; you think something bad might have happened.
- You have lived before, and this is only your current form; you cannot recollect your past lives and do not know if you will survive beyond this one.
- You keep your heart/ liver outside your body and cannot be killed by normal means; your heart/ liver is no longer in the safe place you chose for it.