My favorites are:
1. The (Probably Most Popular) Succbus
http://img1.wikia.nocookie.net/__cb20130530021923/monstergirlencyclopedia/images/thumb/8/87/Succubus_0.jpg/250px-Succubus_0.jpg
2. The Ceshire Cat (A type of Werecat)
http://img1.wikia.nocookie.net/__cb20131228155543/monstergirlencyclopedia/images/4/43/Sample_9125e8607199bf99f69e63fe2ff1faff.jpeg
3. The Youko
http://img3.wikia.nocookie.net/__cb20140125033146/monstergirlencyclopedia/images/1/1e/Sample_e255575abcebb700f9a45ee3b38852903892d8.jpg
And 4. The Valkyrie
http://img1.wikia.nocookie.net/__cb20140624154905/monstergirlencyclo