NamanikuATK
Most known for 棺姫のチャイカ and 装甲悪鬼村正, his design sense and coloring is exquisite! Chaika and Muramasa have
been some of my favorite designs for years now. What I love most about his art is the sense of texture you get from
his brushwork and also how bold his color choices are. His girls are all so lovely.
Nakamura Tetsuya
Known for the legendary eroge, 腐り姫 ~euthanasia~. How he draws faces is very stylized and cute, but the thing
that stands out to me the most is his usage of color. It's so intimate...
Oyari Ashito
One of the greatest ロリコン artists. Check out the games he worked on--the art design in them is spectacular.
His girls are so, so adorable. He draws them in such an elegant manner. I prefer the dreamy atmosphere of his older works, where he mainly worked with watercolor.
Minazuki Tooru
If you're into eroge at all, then you've definitely seen his work somewhere before: he's worked on some of the most influential games in the medium, ToHeart and Shizuku!
Personally, I love the mood and composition in the CGs he's drawn... and the way he draws faces too, so moe!
ZUN
Some people think that ZUN's art looks "bad", but I think it looks adorable. The amount of thought he puts into his character designs too--they're deceptively simple looking,
but they have a lot of tie-ins with the character's mythological/historical inspirations. There's nothing quite like his art.
Takami Akai
The main artist for one of my favorite game series, Princess Maker. Princess Maker 2's DOS release (the one I played the most) especially looks gorgeous!
I love how cartoony his faces can get, and the watercolor-like coloring in his newer drawings is just lovely.