Last month, Apple announced that it would discontinued its Space Gray Magic accessories following its discontinuation of the iMac Pro. The iMac Pro came in a Space Gray finish, and it came bundled with color-matching accessories, including the keyboard, trackpad, and mouse. You could purchase those while supplies last until now. If you go to the Apple Online Store, you’ll see that they only list the white/silver counterparts.
When the iMac Pro originally launch late in 2017, the accessories in Space Gray were not available as separate purchases at the iMac Pro’s launch. However, Apple offered them as standalone accessories a couple of months later. With Apple discontinuing the iMac Pro back in March, Apple has less reasons to continue selling those accessories.
This is not the only time Apple makes color-matching accessories. Apple offers silver/black accessories to complement the Mac Pro, and recently, Apple offers color-matching accessories to complement the colorful M1-based iMac. While you can’t buy these accessories separately, only time will tell if Apple would ever offer them as standalone purchases.