uH

http://www.mangago.zone/read-manga/yandere_hitotsu_yane_no_shita/
http://www.mangago.zone/read-manga/hoshoku_sha_kisumi_kun/
http://www.mangago.zone/read-manga/nani_mo_iwanai/
http://www.mangago.zone/read-manga/haikyuu_primary_target_d_jinshi/
http://www.mangago.zone/read-manga/you_are_still_in_a_bird_cage/ (this one is a GL, not a BL, it was a good short read )
http://www.mangago.zone/read-manga/candy_man/

hmm "psycho love" as a starter cuz its not that bad of a yandere and i even had tears in my eyes, but I recommend reading yaoi webnovels with yandere before reading manga, cuz it gets real dark and it helps to understand how yanderes think differently than from normal love, and a bit how messed up it is...