I was surprised to see such a large collection in Kousaki Rui's Comiket 78 release Tokimeki Mono when he had just released a sizable amount of illustrations for C77 with his GLASS HEART 5 publication. But I guess it helped that several of the illustrations in the last one were reprints. Some of the ones in Tokimeki Mono are as well, but since they were done outside of Kousaki's doujinshi circle, they're new to me ^^
Rui Kousaki's GLASS HEART 5 is another beautiful full-color collection in his great series of illustration doujins put out during the Comic Markets. If you're not familiar with the artist, he has a really unique style (especially with the way he does faces) and does a lot of fantasy-style art work, with knights, armor and elves. Though of course, not all of the illustrations are like that.