Since 2017, Earth Day has been recognized by Major League Soccer — in conjunction with Adidas and Parley for the Oceans — with each team being given a one-off eco-friendly kit that is made of recyclable plastics in order to “address marine plastic pollution.”
The inaugural 2017 kits were white and gray, and were immensely popular among New York City FC supports (I personally wasn’t a fan of them, but it was for a good cause). The next year, MLS unveiled that the “Parley kits” would be dark gray and white. They were also quite popular.