NB-IoT
Cellular service for small, rare messages from devices that stay put.
NB-IoT is a narrowband cellular standard for very low data rates, deep coverage and long battery life on stationary devices; availability varies by country and carrier.
Examples
NB-IoT suits a water meter in a basement sending a tiny reading rarely, using a 200 kHz channel.
A probe sending a 50-byte reading every 15 minutes over NB-IoT stays put, so it doesn't need LTE-M's handover.