List last time was:
-Catherine Calender on Yu's bedroom wall, Yosuke has a bike with an ATLUS label on the side, and what appear to be Nickelback and Linkin Park albums on his CD rack.
-the word TESTED appears at least twice in Chie's story mode. What does it mean? Probably nothing, but whatever, it was worth mentioning.
-Rise makes a pretty good Guilty Gear reference in her announcing before matches sometimes. I hear she also does a Blaz Blue reference, but never played much of that game myself.
-Akihiko's arcade mode also includes a Guilty Gear reference with the "Heaven or Hell" thing.
Now, list some more if you noticed them! And remember, don't mention the Endurance Run! Getting off topic is a pretty serious problem, guys.
Edit: And I'm bad at picking up on these things, so I don't actually have any to add myself. I just made this so there would be a place to put them if someone did catch one.