@tbisaacs mentioned these in his thread about his '21 LX. I could only find a single from another mudder because they've been out of stock for a while. Now they are back (the black ones anyway) They work well and alleviate a gripe I have during anything but local drives.
Toyota Landcruiser 200/300 Series Armrest Black Pair | One Stone Armrests
Black polyurethane foam armrests (pair) for Toyota Landcruiser 200/300 Series. Also fits Prado, Ford Ranger, Hilux, Y62 Patrol & more.
onestonearmrests.com