Digi EX15 LTE Cellular Extender | Available from USAT
This dirt cheap 4G LTE modem on a USB stick can be hacked to run mainline Linux - Liliputing
4G LTE CAT 4 - Airgain
Amazon.com: NETGEAR 4G LTE Modem – Instant Broadband Connection | Supports Power over Ethernet | works with AT&T and alternate carriers (LB1121) : Electronics
Inseego 4G Global Modem USB8L for Business | Verizon