NOTE: This is a review of a product I found on Etsy and purchased. No discount was given in exchange for this review.
As I mentioned previously, Terraforming Mars needs a 3rd party supplement for the player boards. I found several options on Etsy and after some deliberation with Chubby Unicorn, I purchased a set of 5. They work great!
I looked at “overlays” which sit on top of the existing “boards” (which are in fact just paper). The seller I used (and others) offered overlays with a back board which sandwich the player board, but those were much more expensive (1 with a backboard was almost as much as 5 without). Since the main problem had to do with table bumps and accidentally touching the board, and not needing to pick up the player boards, I opted for just the overlays.