For some ideas, I consulted the excellent lists already published by my colleagues Zack Whittaker from ZDNet and Luke Westaway of CNET UK. The actual ranking is rather arbitrary, so have fun complaining about that one -- though with a hot-button topic like this, I think it will be the least of your concerns.
The K5 robot, developed by Sunnyvale, Calif.-based Knightscope, is designed to be a surveillance robot for law enforcement, private security firms, schools and anything else looking for an extra set of eyes and ears on the ground. The 5-foot, 300-pound robot can roam autonomously, sending back real time data about an area with technology that does facial recognition, lidar mapping and 360-degree video. CNET's Kara Tsuboi got a closer look at what makes the K5 robot tick.