Godzilla vs. Hedorah
On the other hand, there are plenty of movies starring man-made monstrosities for Godzilla to fight, and which could be redesigned for modern entries in the MonsterVerse.
One of the better ones from this pool would be Godzilla vs. Hedorah; aka the Smog Monster. After pollution runs rampant, a creature is born from the filth and decay. It threatens to lay waste to the world the same way humans have, and it’s up to Godzilla to set things right with some climactic showdowns.
Though it’s admittedly a bit ham-fisted in its subtexts, this movie wouldn’t be too hard to adapt today. The themes of anti-pollution and climate impact would still be relevant and would offer the perfect way to bring a sleeker, scarier interpretation of Hedorah to the new Monsterverse. Plus, its fight with Godzilla is one of the silliest and most entertaining in the series, which the series will need following Godzilla and Kong’s scrap.