I like quite a few! Dunno if I can call them "favorites" but:
1- Michael Levi (Shingakkou): he's just adorable and cute, I like his VA too.
2-Aoba Seragaki (DMMD): I feel like he's a very nice and warm guy, also his VA is tea.
3- Yoshino (Lesson): dunno if we could call him a protagonist... I...
I think a more proper question would be "what games have you played and ALSO PLAYED THEIR FAN DISK" because most of mine I don't really have the energy or enthusiasm to play the rest of the series lol. I played diabolik lovers! but I'm not sure if I can even call the other games "Fan Disks"...
Honestly, I like both! I don't really enjoy games that are TRY HARDS on making "angsty" content, like Virche for example. but I really like it when they combine both, the protagonist doesn't really need to be cursed in every route and gets the worst end just to MAAAAAAAAAAAAAAAYBE get a happy...
I really don't like FORCING MYSELF to play a game, thus, I play the routes that I wanna play first if I can (so I can enjoy them to the fullest), then I can do the other routes and safely quit the game as soon as I get bored XD