[fundatus]

> It's worth noting that 450MHz was listed as one of the GSM bands, but apparently was never used

It's specified for 4G/LTE (Band 31, 72 & 73) and 5G (Band n31 & n72) as well! The bandwidth is pretty low though at just 5 MHz, but it's used for special purpose stuff like electricity meters. I'm not aware of any consumer devices that use this frequency.