Yeah, there's a bit of lore behind this show that I too have found interest in lately; there's a YouTuber named IcyRoserade who is the king of all things on this show.
Apparently there is a supposed final sixth volume he is in the process of acquiring (Discover Feelings) that one person has been able to find in the wild and is selling to him; from what he said, he should literally be acquiring it any day now, and the biggest question is if there's another "Next time on Peppermint Park" segment at the end that would indicate at yet another volume.
There's also rumor of a Halloween special from which the pumpkin and witch segments would have appeared, but that's just one guy pushing a theory in the YouTube comments section with no actual proof.
It's hard to imagine there was a group of people actually working on this show 30 years ago; that's what makes it so interesting to me - it's more of a fever dream than anything.