Hey, So recently I have been really interested in Taboo themed Romance Dramas of any Asian origin (Taiwanese, Korean, etc..) such as ;

Endless Love (2004) (Taiwanese Drama) - Guardian/Ward

Hello Mr Right (2016) (Chinese Drama) - Teacher/Student

Biscuit Teacher and Star Candy (2005) (Korean Drama) - Teacher/Student

Secret Love Affair (2014) (Korean Drama) - Teacher/Student

Loveholic (2005) (Korean Drama) - Teacher/Student

Majo no jouken (1999) (Japanese Drama) - Teacher/Student

Land of Rain (2013) (Korean Special) - Teacher/Student

Bunjee Jumping of Their Own (Korean Movie) - Teacher Student (and somewhat BL)

Autumn Tale (2000) (Korean Drama) - Brother/Sister (Kind of? not blood related)

I am pretty sure that there are more out there that I have watched but for now I shall just list these... And they don't have to be Teacher/Student even though most I have listed happen to be... You can interpret 'Taboo' however you want, I would just love some recommendations as it feels like lately I have watched EVERYTHING !

Thanks  :)

Boku wa Imouto ni Koi wo Suru (2007) a japanese movie about brother/sister

No, don't worry, there are plenty ^^

Romance (Korean / 2002) :Teacher / student relashionship and the woman's family is responsible for the boy's father suicide.
Dal Ja's Spring (Korean / 2007) : Noona romance. Not much age difference but she minds it a lot.
Hakuba no Oujisama (Japanese / 2013) : Noona romance. And she has a fiancee.
High School King of Savvy (korean / 2014) : Noona romance. A male student impersonates his older brother at work.
I Hear Your Voice (korean / 2013) : Noona romance. It's not the focus of the drama but still, I recommend it.
Oh! My Lady (korean / 2010) : Noona romance. An ajhumma and an actor if I remember it right.
Witch's Romance (korean / 2014) : Noona romance. 39 vs 25 years old, that's the higher age gap I ever watched.
Kou kou kyoushi 2003 - teacher/student

Koi - wife/teacher/student

Mitsu no aji - niece/half uncle

Valid Love - teacher/student, adultery
Transit Girls (future sisters)
I was extremely suprised and happy to receive these responses so quick ! THANKS !!!

@Latifasheraina I remember researching that movie a long time ago and not bothering about it after reading some spoilers bout how the brother had sex with his sister's best friend and that really rubbed me the wrong way... but now that I look back on it again maybe I might give it a try ! Thanks :)

@nastou19 Thank you so much ! I have actually either watched or passed on most of the mentioned dramas when I was going through an intense Noona Romance obsession ! Hehe My fave was I Hear Your Voice.... mostly coz of Lee Jong Suk :p 

@lily_b Generally I'm very prejudice against Taboo Japanese Dramas coz I find they are rather too realistic and disturbing for my taste....(which is odd... considering the most Taboo the better.... guess I want the unrealistic roses are red kind).... BUT then you mentioned one I actually had not heard about, Mitsu no aji, and the plot makes me REALLY want to watch it !!!! Thank you so much!!
@versaillesyoo That plot!! Damn this would have been an immediate fave of mine if it was boys love considering my unhealthy Yaoi obsession !!! I think I shall still try it out though... first GirlxGirl drama ever for me... Thanks !!
I would definitely not call KKK03 realistic but I found if extremely captivating and some kind of wonderful. It can't be explained! But yeah, i suppose it was rather disturbing. If you don't like that, fair enough. :)

As for disturbing, Kanno Miho scared me as the wife in Mitsu no aji! But it was the third Asian drama I ever watched, so don't take it too seriously. (Kanno Miho really is lovely and a good actress and not scary! *lol*) I loved the drama. I could really feel the love between the characers and the heartache. I hope you'll try it. :)
You're welcome. IHYV is one of my fav too ^^ I forgot one because it's not the usual taboo romance drama, it's more a crime drama : Guilty Akuma to Keiyakushita Onna (japanese / 2010). This one is about a policeman falling in love with his suspect.
Seisei Suruhodo, Aishiteruhttp://mydramalist.com/18788-seisei-suruhodo-aishi... ) Adultery, ongoing* Jdrama
Love Song (  http://mydramalist.com/16775-love-song ) Age Gap, Jdrama
Ai Nante Irane Yo, Natsuhttp://mydramalist.com/5178-ai-nante-irane-yo-nats... ) Incest Scare/ "another life", Jdrama (not subbed but worth it). A remake of this drama is That Winter, The Wind Blows a Kdrama, but Jdrama is waaaaaay better.
Taisetsu na Koto wa Subete Kimi ga Oshiete Kuratehttp://mydramalist.com/10-taisetsu-na-koto-wa-sube... ) Teacher/Student, Jdrama
Triplehttp://mydramalist.com/342-triple ) Stepbrother/Sister & Age Gap, Kdrama
Sumika Sumirehttp://mydramalist.com/16056-sumika-sumire ) Age Gap(?) / "another life", Jdrama
Ireland http://mydramalist.com/1287-ireland ) Incest, Kdrama 
Valid Lovehttp://mydramalist.com/10874-valid-love ) Adultery, Kdrama

This is what came to my head first. I really recommend Taisetsu na Koto wa Subete Kimi ga Oshiete Kurate and Seisei Suruhodo, Aishiteru if you live for the drama like I do, lol. Out of these, however, Ai Nante Irane Yo, Natsu is by far my favorite! You totally understand whats going on, even without the subs. (I consider the "Age Gap" dramas I recommended taboo because they feature huge age gaps of 10+ years. Also sorry I'm Jdrama bias haha) I hope you find more of what your looking for :)
Not sure if this is what you're looking for, but there's a Thai movie called "Yes or No". It's about two female roommates in college who fall in love. 
Yuriko Busujima's Naked Diary multi-partner relationships, adultery
My Dangerous Wife adultery, attempted murder (not as serious as it seems)
Little Mom Scandal teen pregnancy
Lipstick juvie + warden
Furenaba ochin
The Rose--siblings fall in love
I Love Lee Tae Ri - 14 year old boy becomes an adult over night and a romance starts between him and a woman.
Hotel King - I don't remember exactly, but they fall for each other while believing they are brother and sister.
That Winter, the Wind Blows - guy fools a blind girl into thinking he's her brother.
My Girl - They have a romance while fooling everyone else they're cousins.
Sungkyunkwan Scandal - the girl disguises herself as a guy and the poor guy thinks he's gay.
Coffee Prince - Same as above.
Which Stare Are You From - haven't seen this one yet, but apparently the guy falls for a girl who looks exactly like his dead girlfriend.
Nine: Nine Times Time Travel - Kinda. Guy sorta becomes her uncle, heh.
Good Doctor - Not taboo, really imo, more makes you think. Guy has the mentality of a 10 year old, but then maybe not really, he's just bit different.
Kinkyori Renai (J-movie) - male teacher/female student - http://mydramalist.com/9795-kinkyori-renai
Doctors (K-drama) - male teacher/female student - http://mydramalist.com/16192-doctors
The Bodyguard from Beijing (HK movie) - http://mydramalist.com/6234-the-bodyguard-from-bei...
The Palace (Chinese movie) - palace maid/prince - http://mydramalist.com/7762-the-palace
Koishite Akuma (J-drama) - female teacher/male student (sort of...you'll see) - http://mydramalist.com/69-koishite-akuma
Fabulous 30 (Thai movie) - older lady/younger man - http://mydramalist.com/9881-fabulous-30