NGFF (M.2) WWAN/LTE/3G/4G to USB Adapter (external enclosure, with SIM-slot) [ 3G / 4G / 5G / GPS ]
Amazon.com: High Speed 4G LTE USB Network Adapter Wireless WiFi Hotspot Router,Share Up to 8 WiFi Users Plug and Play(with WiFi Function) : Electronics
SIM7600G-H 4G DONGLE with antenna, industrial grade 4G communication and GNSS positioning peripheral, global band support
Review of "4G LTE WiFi Modem" hotspot - CNX Software
GX LTE 4G - Victron Energy
This dirt cheap 4G LTE modem on a USB stick can be hacked to run mainline Linux - Liliputing