The Other World - One of absolute favs as a kid. I loved fantasy toys to start with. Had tons of them ranging from He-Man to Conan to little plastic figure playsets. But this early 80s toyline stood out for me even above many higher quality toylines. They were bendy for one, which made them much durable(aka able to take in the tub). They also had a ton of accessories that glowed in the dark. Always a big selling point for me. But the biggest pro for me was that The Other World had some of the coolest monsters and bad guys. In fact, they had more monsters than heroes. I even still have my Froggacuda.
Another favorite of mine was the werewolf looking guy, Weapon's Master. I was always a sucker for characters like that. I especially liked werewolves. I would be willing to bet I still have Weapon's Master in storage somewhere.
There were so many cool figures in this line like a very large Cobra with legs and arms, some dragony things(Sharkoss and Kamaro) that rolled when you pulled them back, and of course the little minions that the main figures came with.
A big thanks to Little Weirdos for the images. There is also a great deal more info on the toyline itself over there. Check it out!