>>8779357They were durably built, so it's easy to find ones that are still in good condition.
A lot of them share the same basic build- buff torso, squatted legs, one "gripping hand" and one open, etc.- making them look like a real "collection" when lined up together, as well as interchangeable with each-other's accessories and vehicles.
But what I think is one of the biggest contributors to everyone's fascination with these things is this: everything that came as a result of the popularity of this toyline is practically its own mythos.
I don't know all the details, but I've heard enough to know that the MOTU molds were iconic to the point have been ripped-off, imitated, or just plain stolen so many times that there are not only bootleg lines, there are bootlegs OF bootleg lines.
There were maybe-maybe-not-official variants you could get through mail-order, there were companies known for having lines that were openly aping off Mattel's line whilst always dancing out of legal trouble, and there are figures with limited release that nobody knew the origin of for literal decades.
Behold, one of the most mysterious and rare figures of all time:
Wonder Bread He-Man.