So I’ve attempted to find every instance of what I call “Kerokey”, an image of Keropii holding a key. So far I’ve found these four:
This one is just obvious:
There’s one on a fan in the staff room in Clannad:
In this one I think he’s actually holding a musical note, but I’m not sure. And of course in the top right corner we have Key’s shameless self-promotion. Actually, I think it’s supposed to say “Key Sounds Label”, which might be why he’s holding a musical note rather than a key.:
I was unaware that it was the actual Key Sounds Label logo.
And of course the one in the drama club room in the bottom left:
There are other instances where you can see what is presumably Keropii, like on Akio’s apron, an Akane CG in Rewrite that’s really obvious, the ace of spades Sakuya’s holding in a CG - if you look at it closely, and you can see Nayuki sleeping with Keropii in a CG, but I don’t count those because they’re not holding anything.
Edit: Unrelated, but I just found this One/Nanase reference in Mio’s route of LB!
LB!, where a random female student is being asked to translate a line:
And One, the scene where Kouhei translates Nanase’s line for her:
And yes, they use the same Japanese phrase when speaking, don’t let the differences in the written English sentences fool you.
Edit 2: Well, that didn’t take long…
Well Riki… I’ve got your answer: