868-MHz wireless module for Raspberry Pi has 2-km range
Connect2-Pi USB 868Mhz Rf Transceiver - OKdo
Wireless Module Cc1101 868 Mhz Module Fhem Cul Transciever Wireless For Raspberry Pi Dropship - Integrated Circuits - AliExpress
LoRa Expansion Board for Raspberry Pi Pico 915Mhz/868Mhz/433Mhz – Oz Robotics
Amazon.com: POBADY 868 MHz Antenna GSM 3dBi SMA Antenna Extension Cable 3M RG174 Cable Magnetic Base SMA Male Adapter Compatible with CCU3 CCU2 Raspberry Pi HM MOD RPI PCB kit ELV kit
RF-based home automation using Raspberry Pi (Part 1) | by Binesh Amarasekara | Medium