#12 is by orange brand: http://danbooru.donmai.us/post/index?tags=orange_brand
Some others I know; #1 is mama ... yeah that's gonna be REAL easy to search, (I'll save you the trouble: http://www.pixiv.net/member.php?id=10358, http://danbooru.donmai.us/artist/show/12119) char is Fujiko Mine from Lupin iii btw.
#4 is sww13 or 极乐之王 on pixiv
#5 I'm guessing is shino: http://danbooru.donmai.us/artist/show/18451