I'm ditto with Yoneda Kou, I love all of her manga ever since I read Kanjou Spectrum. That's got to be one of my favourite oneshots ever! *likes her yaoi funny, simple and sweet*
I am also a big fan of:
- Natsume Isaku: Her ukes are the cutest tsunderes, and all her plots are funny!
- Bohra Naono: I just love the fact that her stories aren't very conventional, i.e.deaf man x porn novelist, blind man x his younger neighbour.
- Sawauchi Sachiyo: Her stories are kinda weird sometimes, but hot and pretty men, hnnghhh.
- Yamada Yugi: I just love any mangaka that could make comedy a pretty big element in an otherwise serious, life-lessons kind of manga.
- Mei Sakuraga: Her boys are all so sexy and I love how she structures her plot.
And one mangaka I'm getting into recently would be Watanabe Asia - I stay away from the original works because I find the plots are kinda outrageous but his/her recent Tiger&Bunny djs are SO. HOT.
Though I'd give Totally Captivated an honorable mention for being my first BL manhwa. I just love how sexy, rich, horny-as-hell Mookyul is totally losing himself over Ewon, and sacrifices everything to be by Ewon's side. Definitely worth reading!