This is a personal favorite:
http://www.mangago.zone/read-manga/negative_kun_to_positive_kun/
Oneshots are usually super underrated, and this one is no exception:
http://www.mangago.zone/read-manga/natsu_no_omoide_haji/
This one is also really cute:
http://www.mangago.zone/read-manga/uchi_no_ouji_irimasen_ka/
This one is a undiscoverd gem:
http://www.mangago.zone/read-manga/rakka_koibumi/
Hope they are to your liking!
http://www.mangago.zone/read-manga/isso_koe_ga_nakattara/ - of my favourite
http://www.mangago.zone/read-manga/ookami_he_no_yomeiri/ - also one of my favourites
http://www.mangago.zone/read-manga/nomi_shiba/ - cute asf
http://www.mangago.zone/read-manga/you_own_my_all/ - a historical BL that isn’t toxic
http://www.mangago.zone/read-manga/kedamono_arashi/ - there’s a series to this n it’s pretty good
http://www.mangago.zone/read-manga/yakimochi_wa_kitsuneiro/ - idk I just like this
http://www.mangago.zone/read-manga/ojisama_to_neko/ - not a BL no romance but so fluffy and so underrated
http://www.mangago.zone/read-manga/rental_onii_chan/ - also not a BL no romance but underrated, non sexual and SO CUTE N SAD
Oui
AHH YOU SHOULD TOTALLY TRY THIS ONES: star x fanboy (its super cute and just a cuteness overload every single time), dream away (the story is super original and its also funny with lovable characters), Heesu in class 2 (really famous for being one of the fluffiest bl's), the best smell (AGAIN SUPER ORIGINAL and its one of my favorites! it made me laugh a lot), Ganbare! Nakamura-kun (its one of the cutests EVER. its short but its completed and totally worth reading), snail pond robber (funny, cute, and made me excited asf when reading it), AND ONE THAT I ABSOLUTELY LOVE IS CASTLE SWIMMERS! (its about mermaids and this one 'mermaid' that is supposed to make the other kingdoms prophecy's come true! you can read it for free on webtoon if its not here), AND THATS ABT IT on my favorite ones! tell me if you read any hehe
pleaseeeee some fluffy sweet bls, some hidden gems and under rated ones or whatever your fav ones are thank youuuuu(づ ̄ ³ ̄)づ