◊1 Litre Of Tears [Drama, Movie] is based on the diary of Aya Kito (if it counts)
◊Antiqua Bakery [Movie] is based off a manga/anime
◊Be With You [Movie, Drama] is based off a novel and a manga
◊Bloody Monday [Drama, 2 seasons] is based off a manga
◊Cat Street [Drama] is based off a manga
◊City Hunter [Drama] is based off a manga
◊Chinese Paladin [Drama] is based off an RPG game
◊Crow's Zero is based off a manga
◊Death Note [Movies, 3 of them] are based off a manga and an anime series
◊Devil Beside You [Drama] is based off a manga
◊Go [Movie] is based off a novel
◊Gokusen [Dramas, Movie] are based off the manga/anime
◊Goong [Drama] is based off a manhwa
◊Grave Of The Fireflies [Movie] is based off an anime
◊Great Teacher Onizaka (GTO) [Movie] is based off an anime/manga
◊Hana Kimi [Dramas] are based off the manga
◊Hana Yori Dango [Drama, Japan] - 2 seasons + movie, Boys Over Flowers [Drama, Korea], Meteor Garden [Drama, Taiwan] - 2 seasons plus special, Hana Yori Dango [Movie, Japan, 1995], Let's Go Watch Meteor Shower [Drama, China] - 2 seasons: all of them are based off of the original manga/anime Hana Yori Dango
◊He Was Cool [Movie] is based off a novel
◊Here Is Greenwood [Drama] is based off a manga/anime
◊High School Debut [Movie] is based off a manga
◊Honey & Clover [Drama, Movie] is based off a manga/anime
◊Ikigami [Movie] is based off a manga
◊It Started With A Kiss [Drama, Taiwan] , Playful Kiss [Drama, Korea], Itazura Na Kiss [Drama, Japan] are based off a manga/anime
◊Jiu [Drama] is based off a novel
◊Kamikaze Girls [Movie] was based off a novel and made into a manga
◊Kimi Ni Todoke [Movie] is based off a manga/anime
◊Kimi Wa Petto [Drama, Japan] , You're My Pet [Movie, Korea] is based off the manga Kimi Wa Petto
◊Koizora [Drama, Movie] is based off a cellphone novel that became a manga and eventually the movie and the drama
◊KO One [Drama] is based off a manga/anime
◊Kurosagi [Drama] is based off a manga
◊Liar Game [Drama, Movie] is based off a manga
◊LIFE [drama] is based off of a manga
◊Lovely Complex [Movie] is based off a manga/anime
◊Meitantei Conan [Drama] is based off a manga (Detective Conan)
◊Nana [Movies] are based off a manga/anime
◊Nobuta Wo Produce [Drama] is based off a novel
◊Ouran High School Host Club is based off a manga/anime
◊Paradise Kiss [movie] is based off a manga/anime
◊Rurouni Kenshin [Movie] is a live-action soon coming out that's based off a manga/anime
◊Sand Chronicles [Drama, Movie] are based off a manga
◊Secretly Loving You [Drama] is loosely based off the manga Hana-Kimi
◊Startling By Each Step / Bu Bu Jing Xin [Drama] is based off a novel
◊Summer's Desire [Drama] is based off of a novel that was turned into a manhua which became a drama
◊The Prince Of Tennis [Drama, China] [Movie, Japan] is based off a manga/anime
◊Usagi Drop [Movie] is based off a manga/anime
◊Yamato Nadeshiko Shichi Henge [Drama] is based off of a manga/anime
◊Yokai Ningen Bem (I heard is also an anime)
◊Zettai Kareshi [Drama] is based off a manga (Absolute Boyfriend)
-The ones bolded were already mentioned
-The ones in this color I have not seen or have not finished yet but know are based off of a novel/manga/anime
That's all I can think of at the moment haha, I skimmed through my Plan to Watch list and went through my completed list :p
