Mignon

Romance, art and plot: the best animated BL Korea has to offer, both starring hot and cute pairings with great chemistry. Same format, style, studio and director, with similar highly erotic final/special episodes. The main difference is Mignon being a vampire x sports story and Hyperventilation having a school and slice of life theme. 

Another short-form series about two male lovers; both are relatively light (perhaps Semantic Error a bit more so), both are fun series that can be completed quickly; you may find overlap between art styles somewhat 

Animated by the same Korean animation company ABJ Company who also animated Hyperventilation and Ubelievable Space Love. Both of these works were made by Bboong bbang kkyu, both korean manhwa series. If you're looking for spicy, fresh storylines, and beautiful, yet simple character designs, these are for you! 

Two short and dark works, of the rarely animated vampiric BL genre, following a peculiar duo at work. The plot is compelling, the animation is solid, the fights are bloody, the guys are hot. The romance and sports-centered Mignon is much more sexually explicit in its latest episode, while Vassalord is heavier on the horror but subtle with the boys love.