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You probably read these but still I would recommend:
At the End of the Road
Jazz for Two
How Sweet is a Sugar Daddy
Escape Journey
Megumi and Tsugumi
Lonely to Organdy
Raion Gotoki no Kuni Kara
I forgot some of my fave underrated BLs since it's been years. BTW, I also recommend the other replies' lists! I love them too...
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I don’t know what ur looking for but one I go back to a lot
-it really cute and even now I’m gonna reread right now
https://www.mangago.zone/read-manga/ao_to_midori/
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Stanning 101, We only held hands, December rain (Not the new one, it was kinda old), My darling sign in, 1866, keeper of the pearl, Dragons first crush, A Paramore, Love tractor, Zero at the bone, Kedomo arashi, A song of blood and fire. These are all absolutely gems my friend, you won't regret reading them especially the ; Stanning 101 and my darling sign in. There's so much more but this will do for now ٩(๑❛ᴗ❛๑)۶
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Keeper of the pearl ( kinda got known tho )
Star x Fanboy
Define the relationship
Love tractor
Kobutsu wa Itoshii Anata no Hara no Naka ( there are like works of diff couples in the same verse! )
Runaway Assistant Ha!
Mr. A & Mr. B
Faked ( author is literally on mangago T^T)
It's not like that
A painter behind the curtain ( fucked me so bad )
Don't forget I like you
There's more but yeah, some of these probably got recognition through tiktok but when shit was down. I don't know who else have read these, especially the short mangas.
imagine I'm that friend who you want to share ur best underrated BL. What would u recommend.?