Conexio Technologies' Stratus is an open source LTE-M/NB-IoT Cellular-IoT development kit based around Nordic Semi nRF9160. Stratus can charge battery from solar power & comes with 500 MB global data plan. Stratus will be available on Crowd Supply.
Nordic Semiconductor's nRF9160 is a low power LTE-M and NB-IoT wireless modem available in a small footprint System-in-Package and is targeted for Cellular IoT applications.
Arduino Pro has released a remote monitoring and control solution called Arduino Edge control. The board features uBlox Nina B306 BLE 5 module and two Arduino MKR expansion slots.