iMovR's Trackless Keyboard Tray is an all-around solid option for an ergonomic keyboard tray, featuring 15 degrees of negative tilt and an optional independently adjustable mouse platform. While it may not be the best option for treadmill desking, non-treadmill desk users will find that the Trackless Keyboard Tray feels much better to type on that other under-desk options.
Fellowes Professional Series Sit / Stand Keyboard Tray Review
The Fellowes Professional Series Sit / Stand Keyboard Tray is functional a functional ergonomic keyboard tray, but it offers little more than that. Stability issues keep it from being top in class. Perhaps its branding is its biggest fault, as it cannot provide true sit-stand utility on its own.