Okay, I'm pretty sure you've read them all by now, but I'll give you some titles which either I like or love and don't see very often commented around here. Sorry if it ends up being useless ╮(￣▽￣)╭
http://www.mangago.me/read-manga/pink_takaguchi_satosumi/ <- kind of a bad ending, but very fun (I like the ending, tho)
http://www.mangago.me/read-manga/sakende_yaruze/ <- I adore it, one of my first completed yaoi
http://www.mangago.me/read-manga/lucky_kun/ <- Don't miss this one :3 Also bad ending, but that's how Satosumi works
http://www.mangago.me/read-manga/kinou_nani_tabeta/ <- kind of a fun slice of life, refreshing and real
http://www.mangago.me/read-manga/ai_towa_yoru_ni_kizuku_mono/ <- historical with butler and queen uke
http://www.mangago.me/read-manga/gerard_to_jacques/ <- historical with an interesting setting
http://www.mangago.me/read-manga/orokamono_wa_aka_wo_kirau/ <- historical, spain, beautifully written 10/10
http://www.mangago.me/read-manga/ultras/ <- I just love how sexuality has so little importance in this manga. As a person from a country with great soccer history, this feels very refreshing
http://www.mangago.me/read-manga/soldier_zin/ <- interesting one-shot
http://www.mangago.me/read-manga/animal_x/ <- very well known m-preg manga. It's action-packed. I don't think many people like it, but it's pretty different.
http://www.mangago.me/read-manga/tantei_aoneko/ <- idiotic take on both Sherlock and Arsené Lupin. It's soo fun, but soo confusing.
http://www.mangago.me/read-manga/sono_toki_heart_wa_nusumareta/ <- simple manga about masked thieves. People remember the extra one shot better.
http://www.mangago.me/read-manga/amai_hari/ <- waiting for update... hahhh u3u
http://www.mangago.me/read-manga/zetsuai/ <- one of my favs. Actually very well known. But people tend to ignore it for some reason =O (art lol)
http://www.mangago.me/read-manga/partners/ <- Unique manga, worth a read. Don't mind the art
http://www.mangago.me/read-manga/d_j_vu_monchi_kaori/ <- Kaori Monchi building some confuse stories as always, but she knows how to do them sexy! Dayum!
http://www.mangago.me/read-manga/bannin/ <- I love how her stories are always so ambiguous. But they're very enjoyable.
http://www.mangago.me/read-manga/metro_dog/ <- interesting and simple slice of life
http://www.mangago.me/read-manga/blood_yura_tamaki/ <- great story, rushed but unique. Has a seinen flavor.
http://www.mangago.me/read-manga/the_man_of_tango/ <- Delicious tale of passion. Long live different characters.
http://www.mangago.me/read-manga/thrill_or_sweet/ <- Silly one-shot. I like it :3
http://www.mangago.me/read-manga/casino_lily/ <- Other of the first yaoi manga I've ever read. Short but fun.
http://www.mangago.me/read-manga/fake/ <- If you haven't already read it, don't miss it ò.o
http://www.mangago.me/read-manga/boys_next_door/ <- It's more of a josei/seinen, but it's an interesting story. My first BL manga. Don't like it as much now (it's kinda forced) but worth a read.
http://www.mangago.me/read-manga/anxiety_of_soul/ <- I like this manga, despite the tragedy.
http://www.mangago.me/read-manga/ihoujin_etrange/ <- Eccentric, but interesting. I like the shounen-esque characters.
http://www.mangago.me/read-manga/seikimatsu_tantei_kurabu/ <- Sherlock and Watson manga. Horrible drawings. HORRIBLE. But I don't think they were meant to be pretty lol
Wow. So many. I'll check them out later. Thanks.
Any awesome underrated yaoi you know? Thanks a bunch.