Pastel Memories

Both series are about "Anime" Both have a lot of easter eggs and references to other anime Animegataris is about a group of students creating Anime research club Pastel Memories is about a group of girls saving literal Anime/Manga/Light Novel world from viruses 

1. A slight part of Japan is invaded/infected by mysterious existence that causes it to lose its culture and creativity (and cuteness too). 2. People lose their minds/memories. 3. Cute girls are there to fight the mysterious existence and return their hometown and people back to normal. The peaceful life of people and their beautiful culture are at cute girls' hands! 

Both anime have a similar premise where characters travel to fictional stories from our world. In both anime these stories are corrupted and the main characters have to fix these stories so that they become familiar to us again. In Pastel Memories the stories are Japanese anime (GochiUsa, Rozen Maiden etc.), while in Grimms Notes the main characters travel to western fairy tales (Cinderella, Aladin etc.) The main difference is that Pastel Memories covers a wider range of genres and has a full female cast (and the characters have more fetish points); while Grimms Notes has a better art style.