Total Recommendations: 9
Both are 6 three-minute special episodes FILLED with ecchi.
Both have aliens in them. In Denpa Onna Erio believes she's an alien, but she's not unlike Nyaruko who is.
Probably the most similar, both can put a smile on your face. They tell about 3 sisters and each is similar. They both have sisters from the same age groups. Both are comedy too.
PapaKiki tells about sisters and both are comedy. PapaKiki has an anime adaption.
Both tell stories about sisters and their goofy adventures. CxC is more ecchi, while AkaPro is shounen.
Both are hilarious and cute, and have a similar art style somehow
Both have a magical anime witch girl with pink twintails in it from a children's anime. OreImo was Meruru, while YuruYuri has Mirakurun.
Both are cute, and give off a relaxing aura.