Concept artist Zachary Berger has worked on a number of films including Logan, The Mummy (2017), and Kong: Skull Island. His art shows early concepts and designs for the many creatures and and visuals of Kong: Skull Island, below we have some of his art with a brief explanation/speculation (ours, not his).
These few shots give a very good idea of what the arrival to what Skull Island would look like, he seems to have gotten pretty close to the final film, the ship, the storm, and the visual of first seeing Skull Island.
Wall concepts, while these designs never made the film they show a more modern version of the famous wall, be built from some type of stone blocks, it possible the film makers felt it was to modern.
Flying creatures, his concepts show designs that would have fit into nature, the wings having the look of leaves, as well as very deadly features like a serrated beaks. While a version of these made the film it would have been interesting to have learned more about them based on these concepts.
Skullcrawlers, his designs definitely show the starting point of the Skullcrawlers we ended up in the film. He based them directly on the original creature in the 1933 film and gave them a more modern look, with more pronounced features of the original creature. We got some of these in the final design but his design is much closer.
Skull Island visuals, while the bottom pic is pretty close to the final films "Boneyard", the top one shows a much more interesting altar to Kong's kind by the islands natives. This would have looked great had it been done.
His concept of Kong is right on the mark, very close to the design and scale in the final film.