Amazon has removed many, but not all, brands of hoverboards from its website following reports of the popular Christmas present catching fire. Without any public announcement, models of the self-balancing scooters from makers like Swagway and Phunkeeduck have disappeared from the online retailer. Hoverboards from brands like Jetson and Razor remain for sale. On Friday, Amazon asked Swagway to provide documentation that its boards' batteries and chargers meet safety standards, according to Swagway.