In 1968 George R. Romero made one of the greatest and most revolutionary films of all time. And he fucked up copyrighting it. And that resulted in the single most confusing list of sequels, remakes, knockoffs, and reedits in all of film. Others have done a better job than I could to map it out and make sense of it but I couldn't find a Letterboxd list so I figured I could contribute that much. If you want to find out more check out those others' hard work.
www.youtube.com/watch?v=ZZoqZxgw7HU
smugfilm.com/mappingnight/
i.imgur.com/RY9Vmx1.jpeg
Note: I left out the entire Italian Zombi side of this because well... they're really not sequels or knockoffs, just someone throwing a brand on their movie. But that's a whole other confusing mess.
But feel free to mention any I missed or you think should be added.