Just my personal favourite yaoi/shonen ai mangas so no particular theme here...
But, since it's my taste you might see some kind of pattern repeating itself? Haha. I like well written love and lovesick boys which means I enjoy a bit of angst from time to time...(and smut).
Order: I sorted them by autor, in alphabetical order
*Underage is when there is a relationship between an adult (20+) and a teenager (18 or less)