Rides with no villain. . .
Space mountain
Haunted mansion
Pirates of the caribbean
big thunder railroad mountain
tower of terror
flight of passage
plus many more
I don't think a villain is needed to have conflict. Lots can go wrong without it being malicious or on purpose by a villian. We have no idea what will lead us to the drops or cause us to have to take on the drops, all know is Dr. Facilier is not in it.