3.5, 3.7 GHz 1800. 2100. 2300. maybe even 700 can work just like LAA. Qualcomm, Verizon, and AT&T testing convincingly shows that commercial quality broadband can be delivered today over unlicensed spectrum. The telcos are targeting the Wi-Fi bands and possibly 3.5-4.2 GHz.
The same technology can be used to recover spectrum in licensed bands like 1800 & 2100, Especially in rural areas, massive amounts of licensed spectrum lie fallow. It would be enough, for example, to deliver a true gigabit of rural broadband.