Second chance romance.
Slow burn.
One of them breaks up even though they don't want to.(In Lighter and Princess the main lead breaks up and in Fireworks of My Hard the female lead breaks up)
Female lead reaches out first after they meet after years.
Main lead is hesitant to be with the female lead again.
Main lead's parents have died.
Female lead's parents are against her being with the main lead.
Female lead goes against her parents for the Main lead.
Female lead is rich while main lead is poor.