HC-12
The HC-12 is a serial bridge on the 433MhZ band. It is a Hope SI4463 integrated with a microcontroller that allows very a simple AT protocol for serial communication. For this band the range is incredibly good.
The device is simply a serial link as as such needs only a spare UART. The library here however allows for access to the AT command so that various modes can be used.
// #include "http://www.byvac.com/mBlib/flb/Library/2016/lib_HC12.bas"