These! http://www.mangago.zone/home/mangalist/995604/
I actually stayed up all night reading Warehouse like I literally couldn't stop reading (beware the tw tho). A lot of these are pretty popular so not "hidden gems" but they're very good and I'd recommend them.
http://www.mangago.zone/read-manga/a_proxy_painter/?wjO7
http://www.mangago.zone/read-manga/the_beast_must_die/?Vt7r
http://www.mangago.zone/read-manga/black_mirror/
http://www.mangago.zone/read-manga/ventham/
http://www.mangago.zone/read-manga/decision_webtoon/
http://www.mangago.zone/read-manga/legs_which_cannot_walk/?HCMk
Can anybody recommend me BL or Yaoi with a plot that makes you really hooked to the point that you want to stay up all night reading hnnng. Give me those hidden gems (づ ̄ ³ ̄)づ