Dean or Jess from Gilmore Girls. Maybe Dean in actuality. Jess is attractive but only somewhat in fantasy (they're both fictitious but that's not the point), because he's interesting. Dean is better boyfriend material, imo. Just because he seems nicer and more caring.
L - Death Note
LeLouch - Code Geass
Mikasa - Attack on Titan
Finny - Black Butler
Naru - Ghost Hunt
Taiga - Toradora
Tomoko - WataMote
Yato - Noragami
(I have no shame that these are all anime characters)
I have a thing for Yandere type characters most of all Yuno Gasai from Mirai Nikki
I don't know. Maybe I like being at the center of thought of somebody and the grotesque thought that she would kill for me or for her whatever is actually ... cute
I also like the emotional "problematic" type which Yuno also falls under and Lucy from Elfenlied. And I like pink hair somehow
Nagisa from Clannad is also great.
But I wouldn't necessarily date but marry them immediately haha :'D