Yaoi

They are all kinda popular as only really good mangas get more than one volume, but some of them are a little bit older so I hope you haven't read all of them yet :)
http://www.mangago.me/read-manga/hana_wa_saku_ka/
http://www.mangago.me/read-manga/mabataki_no_aida/
http://www.mangago.me/read-manga/koi_to_wa_yobenai/
http://www.mangago.me/read-manga/rutta_to_kodama/
http://www.mangago.me/read-manga/himegoto_asobi/
http://www.mangago.me/read-manga/ano_hi_no_kimi_wo_dakishimeta_nara/
http://www.mangago.me/read-manga/sorenari_ni_shinken_nandesu/
http://www.mangago.me/read-manga/punch_up/
http://www.mangago.me/read-manga/complex_manda_ringo/

Hmmm...
Let dai
Slow starter
Running on empty
Menkui!
Itoshi no nekokke (the sequel is longer tho)

These are at least the ones i can think of, and i really don't know what counts as "popular".

most of my favorites are long manga so
http://www.mangago.me/read-manga/genwaku_no_kodou/
http://www.mangago.me/read-manga/yellow/
http://www.mangago.me/read-manga/innocent_bird/
http://www.mangago.me/read-manga/taiyou_no_romance/
these are shounen ai but still really good --
http://www.mangago.me/read-manga/koori_no_mamono_no_monogatari/
http://www.mangago.me/read-manga/g_defend/
http://www.mangago.me/read-manga/jinjuu_houretsuden/
http://www.mangago.me/read-manga/asterisk/
http://www.mangago.me/read-manga/komatta_toki_ni_wa_hoshi_ni_kike/
http://www.mangago.me/read-manga/switch/

hopefully you havent read some of these already!

http://www.mangago.me/read-manga/hanaya_no_nikai_de/

http://www.mangago.me/read-manga/tsumibito_no_kiss/

http://www.mangago.me/read-manga/meikon/

http://www.mangago.me/read-manga/toiki_ni_furete/

http://www.mangago.me/read-manga/akuma_to_issho/

http://www.mangago.me/read-manga/jouzetsuna_yubi/

http://www.mangago.me/read-manga/ousama_game_takagi_ryo/

http://www.mangago.me/read-manga/aishuu_no_kanon/

these and some more are in this list: http://www.mangago.me/home/mangalist/56720/?filter=&page=1

Thanks I read some but for the most part there all new to me. Really appreciate it