I recommend scanning your 300-440 MHz range - there's an amazing number of devices working in it. Garage remotes, car remotes, smart power meters, ACs, weather stations, tire pressure monitors, I can see 3 periodic signals at home and I don't even know what 2 of them are. (maybe picking up something from neighbours)
Don't forget the 900mhz range! Plenty of cool stuff going on there. Oh, and you could make a searching antenna pretty easily- basically a shitty antenna that you can use to find signal strength easily, because it picks up so poorly.
