Transformers (Hasbro, 1984–present)

Ever tried to transform a Transformer without a PhD in mechanical engineering? Yeah, me neither. But let's get real—when it comes to the 'Greatest Action Figure Lines of All Time', Transformers are basically the rock stars. Where else can you get a truck that turns into a giant robot? Sure, you might spend hours figuring out whether the left leg folds before or after the right arm twists, but that's half the fun, right? Plus, the fan debates alone could fuel a small power plant. Whether it's Optimus Prime's leadership skills or just trying to keep track of the different series, Transformers fans are in it for the long haul.