There are currently two types of Grassy Plateaus Caves known to exist: the Tiger Plant Caves and the Sea Crown Caves. In addition to this, there are two Tiger Plant Caves, and six Sea Crown Caves in total. They are all located reasonably close to each other.
Eight of the thirteen Sea Crowns on the map can be found in these caves.
The Sea Crown Caves are found within the Grassy Plateaus. Numerous amounts of flora can be found in these caves. Hence the name, there is a large quantity of Sea Crowns found within. Other Flora such as Violet Beau or Regress Shells can be found here too. What was once the 'Overgrown Caves' is now a larger version of the Sea Crown Caves connected to a strange naturally formed crater with similar Flora.
The Tiger Plant Caves, as the name might suggest, are characterized by an abundance of Tiger Plants, making it very dangerous for the player to navigate. Several other bioluminescent plants can be found here as well, creating very interesting lighting effects.