maybe you'd like Worldend: Debugger? it's survival plot and a little bit of BL subtext like Seven Princes. The Promised Neverland is a really good survival plot.
I think Ana no Mujina and Conductor are similar to Yuukoku no Moriarty. Ana no Mujina is about a clever conman and his group of friends who con bad people. In Conductor, *spoiler* there is an anti-hero who orchestrates a string of events that lead to bad ppl killing each other, but s/he doesn't reveal his/her identity until the end.
or you can just read the Sherlock manga
oh wait!! this manga is really similar to Seven Princes: http://www.mangago.me/read-manga/torikago_no_tsugai/ because they get locked in a maze-like place and try to find a way out.
Thank you so much for your recommendations +//v//+
I liked the Worldend : Debugger hoho i think i've been aiming for the BL subtext all along just that i didn't know what it was called hehe .
np ^^ mangaupdates has tags as "BL subtext" and "boys' love as subplot". maybe these could help
http://www.mangago.me/home/mangatopic/1721494/
http://www.mangago.me/people/tag/49344/BL+undertones
http://www.mangago.me/home/mangalist/187833/
Would anyone be kind enough to recommend me a manga that's like Yuukoku no Moriarty or Seven Princes of the Thousand Year Labyrinth ?
Thank you in Advance (≧∀≦)