LoRaWAN is interesting.
RNode - Integrated, long-range data-radio that uses raw LoRa modulation in a variety of frequency bands.
TinyGo - Go compiler for small devices, based on LLVM.
Particle Store - Many cool IOT products to buy.
TinyFPGA - New series of low-cost, open-source FPGA boards in a tiny form factor.
Lacuna - Low-cost, simple and reliable global connections to sensors and mobile equipment.
Tock - Secure embedded operating system for Cortex-M based microcontrollers.
Shodan - Search engine for Internet-connected devices.
Sonoff-Tasmota - Alternative firmware for ESP8266 based devices like iTead Sonoff with web UI, rules and timers, OTA updates, custome device templates and sensors support.
Dumbass Home 2.0. (2019) - Internet of Things. How to Automate Your Rented Box Today.
Amazon FreeRTOS - IoT operating system for microcontrollers.
Senet - Cloud-based network connectivity platforms for the on demand build-out and management of the Internet of Things.
TDengine - Open-source big data platform designed and optimized for the Internet of Things (IoT).
WebThings Gateway - Web of Things gateway.
NATS - High-Performance server for NATS, the cloud native messaging system.
Liftbridge - Lightweight, fault-tolerant message streams.
OpenMQTTGateway - MQTT gateway for ESP8266, ESP32, Sonoff RF Bridge or Arduino with bidirectional 433mhz/315mhz/868mhz, Infrared communications, BLE, beacons detection, mi flora / mi jia compatibility, SMS & LORA.
Arm Mbed OS - Free, open-source embedded operating system designed specifically for the "things" in the Internet of Things.