= couples who are blood-related or know each other somehow otherwise
additional are the series in the following lists:
http://www.mangago.com/home/mangalist/6968/
http://www.mangago.com/home/mangalist/7543/
http://www.mangago.me/home/mangalist/8347/?filter=&page=2 (just the Kuroneko series)
That main character was already powerful or intelligence or at least in one 'ability' of talents.
In any genre, (Mostly shounen but can be some shoujo)
In first few chapters that person had shown that person already strong enough to beat few or many people in beginning of few chapters. Or person realized that they has a talent in something and its very good.
It's can be come from hard work, natural talent, gain the talent, or hide talent.