Hidoku shinaide
Viewfinder
Crimson spell
Love stage
Koisuru boukun
Hoshi no Yakata
Katekyo!
Eleketel delusion
Aitsu no Daihonme
Ten count
Kokoro (kanda neko)
Honto Yajuu
Ameiro paradox
Kigurumi planet
Sweet blood
Konya mo nemurani and it's sequel kimi to kore Kara
Kirepapa
Junjou romantica
Sekai ichi hatsukoi
That's all I can think of at the moment that I've read. Hope it helps
Rutta To Kodama ( completed )
http://www.mangago.zone/read-manga/rutta_to_kodama/
Usagi Otoko Tora Otoko (completed )
http://www.mangago.zone/read-manga/usagi_otoko_tora_otoko/
Konya mo Nemurenai ( completed )
http://www.mangago.zone/read-manga/konya_mo_nemurenai/
Ameiro Paradox ( ongoing )
http://www.mangago.zone/read-manga/ameiro_paradox/
Very different styles in terms of art, so if you see one you like better, explore more of that artist's work ^^
http://www.mangago.zone/home/mangalist/116625/
This is a list of all the Yaoi manga I read, the ones I listed are one here and many more, not all of them are 12+ chapters but there are others that I didn't mention. So if you want to just look for new ones in general check it out. ( ^ω^)
i like long stories so i'm looking for a long yaoi manga (12 chapters or more ) plz give me all the long ones and thnx ┗( T﹏T )┛