Getting Gigabit Networking on a Raspberry Pi 2, 3 and B+ | Jeff Geerling
Amazon.com: 4G/3G/2G Raspberry Pi Communication SIM7600G-H M.2 HAT with GNSS Positioning and High Speed LTE CAT4 Global Band Connection for Networking Cloud Phone Call/SMS etc @XYGStudy (SIM7600G-H-M2 4G HAT) : Cell Phones
Raspberry Pi as a router using a single network interface
Building your own Router with a Raspberry Pi — Technically Wizardry
Raspberry Pi Zero W WIFI performance - NotEnoughTech
Converting a wifi router into a case for the Raspberry Pi - Raspberry Pi Pod and micro:bit base