Earthian, Angel's Feather Recommendations
Earthian and Angel's Feather are remarkably similar in almost all points. Both follow the same general plot of two opposing factions of angels fighting for supremacy. More, these two OVAs involve shounen-ai overtones (perhaps more pronounced in Earthian but very clear in AF as well) that make for some of the more dramatic moments. Earthian has a more dated look while AF is visually much more modern; seen side by side these two anime provide an interesting comparison.
Both are OVAs that involve angels, bishonen and BoysLove. Earthian is a BoysLove classic, so it's animation might be a bit old fashion, especially the first two episodes. Angel's Feather on the other hand is very beautifully animated.