In the Garmin Edge line, models higher than the 200 have Ant+ wireless capability that allow speed sensors to provide this data in the absence of GPS signal. HR and cadence have nothing to do with GPS functionality, but in the Garmin line, they use ANT+, which is only available on higher end devices. Wahoo will also have similar offerings. I don't know if the Fenix watches will pair At lower price points you can purchase non-GPS old school "cycling computers" that provide speed metrics. These devices of often well under $50, and you can't get any data off the unit. The data is collected by counting the wheel revolutions and multiplying it by the wheel circumference which is user settable.

If you already own a fancy GPS, look to see if it can be paired with any external speed sensors.