Ah, that’s a tough one! I haven’t been doing in-store releases for that long (approx. 7 months), so I can’t say from a veteran’s point of view. However, the most unpopular I’ve seen so far (not including the random unannounced releases) have been either Fancy Paper Dolls or the Sweet Cream House re-release. They barely made a blip on people’s radars.
Hope you have an awesome day too! ^^