Free site:
Steel Heroines Vol 1 ~Kusuha~ by Youkai Tamanokoshi, a Super Robot Wars doujin.

Member Site:
Mermaid no Youni by Azuki Kurenai. Be warned, this has dickgirl in it.

Daikyonyuu by Bijogi Junction.

Ura Bosei Yoku by Bijogi Junction.

Dokkin Bishoujo by Caramel Dou. This has some dickgirl, lactation, and BE in it.

Haha Wa Sekushi Aidoru {My Mom Is A Sexy Idol} Vol 1 by Chanpon Miyabi.

Haha Wa Sekushi Aidoru {My Mom Is A Sexy Idol} Vol 2 by Chanpon Miyabi.

That is all.