I am at the point in my campaign where each arc is going to be character centric. I have already done one, but now I need help fleshing out the others. I want each arc to be about 2-3 sessions each. The characters are currently level 8 and will gain a level after each arc is completed. The characters own a tavern in Waterdeep, but have become somewhat of celebrities as both figures and as a group of strength, having since been sought out twice for difficult jobs to complete.

1. A human man who died and is no longer with the party was revealed to be a Zhentarim spy that had given notes on how to kill each of the party members to his Zhentarim boss, The Dread Lord.
2. An aasimar woman who had her life taken by her lover to ressurect a God (who chose duty over love) and also had her soul unwillingly sold to Asmodeus.
3. A human man who solved a slave trafficking pirate group that was linked to the drow in the Underdark, one of whom he nursed back to health and lives in his basement, hiding from all others besides the man who rescued her.
4. A loxodon man who was killed in a war against a bugbear army, resurrected by elves who taught him magic, only for him to horribly disfigure the elven prince and forced to go on the run.
5. A half-orc man who was forsaken by both his orc people and human people, his father is a leader of a vicious orc raiding pack that also killed his mother.

Literally any kind of hooks or events that could carry these threads further, I would appreciate any help!

I love character centric arcs and I think the players really like seeing their backstories actually mean something. In terms of basic ideas:

1. The Zhentarim kidnap the players and they have to escape the dungeon of the Dread Lord.
2. She needs to get revenge against her lover and attempt to get her soul back from Asmodeus, though I think you may need to wait to get much higher than level 8 to take on Asmodeus lol
3. Maybe the group is taken, or people close to the group are taken by these same slave traders and they have to find clues that eventually lead to the Underdark.
4. The bugbear army that killed him could be angry that he didn't stay dead and they are here to claim back their kill by laying siege to Waterdeep unless the Open Lord gives them back to them. Or you could change that to the elven army. Or have the bugbears and the elves team up.
5. There isn't a lot to work with here, besides the characters run into the raiding party, so you would need other variables to spice this up and turn this into a larger arc. If you don't use any of the above hooks, you could use them here, the orcs lay siege to Waterdeep or kidnap some people close to them.