But that doesn't mean that the First Order couldn't have their own super star destroyers, right? If they could turn an entire planet into a star system destroying doomsday weapon, why not? Which is now a mountain of scrap on Jakku. And the last one in Imperial hands (officially) was the Ravager.
The new canon says that there were only thirteen Executor-class Star Dreadnoughts in existence. But thanks to the new canon, we have to rethink on how many there are now flying around. It is basically the size of Manhattan armed to the teeth. When you saw it, you know that this was the one ship you didn't want to mess with. I've always loved the super star destroyer in the Star Wars films.