1. black mirror
2. mad dog
3. red candy
4. kill the lights
5. golden light for you
6. the summer hikaru died
7. i have to be a great villain
8. got dropped in a ghost story, still have to work
9. murderer llewellyn's enchanting dinner invitation
10. dead man switch
many more in here (●'◡'●)ﾉ https://www.mangago.me/home/mangalist/3445940/
This one is goat
https://www.mangago.me/read-manga/dreadful_night/
Gsgw is not a BL, but it's definitely a horror thriller novel.
Feeding lamb
I'll rec some manhwa/manga other than the ones already listed, but honestly the best BL horrors imo are unlimited flow danmei.
The art in Falling Sheep is top tier https://www.mangago.me/read-manga/falling_sheep/
MadK is rlly unique but not exactly horror/thriller https://www.mangago.me/read-manga/madk/
Truth or Dare has an interesting premise https://www.mangago.me/read-manga/truth_or_dare/
The Mansion Summoned by Ghosts is okay... https://www.mangago.me/read-manga/the_mansion_summoned_by_ghosts_cupid_scans/
What are y’all’s favorite BL horrors/thrillers !!