I’ve quintuple checked & one nature card is indeed missing even going through all of the entries trying to find something that upgrades/is replaced by “???” turned no results; most likely it’s just a bug or a card forgotten to be implimented - or maybe a card that you can only get through those disaster events & is super rare?
e: looking @ the tech tree it seems it was the last option, a card obtained only through 2 disaster events tech tree, made by user wondible
e2: yep, managed to get it by making a bunch of ‘massive mining’ cards (fossil power branch)