Manaria Friends

Both have the same lesbian relationship involving dragon and human but while one was more of comedy the other one was more like a soft drama.  

Both take place in high schools and feature mythological/supernatural characters alongside humans. "Interviews with Monster Girls" features vampires, dullahans, snowwomen (or Yuki-onna) and succubui, while "Manaria Friends" features dragons. They differ in that "Interview with Monster Girls" takes place in modern Japan but it just so happens to have these supernatural beings, while "Manaria Friends" is in a different world all together and human characters have the potential to learn magic. 

Both are about female characters at a magic academy school in a fantasy world. Both also feature beautiful background music and gorgeous animation. 

These two anime have a similar calming atmosphere, detailed backgrounds, and an emphasis on friendship. Manaria is shorter and thus more limited in scope while Aria is much longer (and has sequels). Each is well worth the watch, however, for anyone looking for a soothing and quietly enjoyable series. 

Both have a similar art style, a similar mood and both showcase different creatures with magical abilities. Both have comedy aspects too.