Concept artist Jerad S. Marantz worked on Batman v Superman, and he was back for Justice League as well.
Marantz shared two of his Justice League designs on Instagram. The first, shows off Ben Affleck’s new “tactical” Batsuit. Based on the concept art, it doesn’t look like the final design was changed very much. He also shared one of his early designs of a parademon. I think it looks scarier than what they ended up using for the movie. Check out the new concept art below.