I don't know if anyone else has been as clumsy as me, but I dropped my cell phone and credit cards in between the seat at least 6 times before I fixed the problem. I have the black interior and these filled the gap and blended in perfectly, don't bunch up or move when the seat is adjusted, and most of all - stopped me from having to fish under the seat for things I keep dropping.
https://www.amazon.com/Drop-Stop-Original-Patented-Filler/dp/B00BYH6C1E
https://www.amazon.com/Drop-Stop-Original-Patented-Filler/dp/B00BYH6C1E