I know what you mean, but I still can't tell the difference between The Ninja Force, Ninja The Protector, Full Metal Ninja, and Ninja Terminator.
Those movies were produced en masse with little to no regard to copyright, contracts with actors or global quality and that pretty much fits the definition of slop.
Aside from the so-bad-they're-good ninja scenes (always a pleasure to see a ninja turning into a wooden stick in a park), I just find those movies boring.
Relevant XKCD : https://xkcd.com/1220/