This Flame Sensor is sensitive to the flame, but also can detect ordinary light. Usually used as a flame alarm. 

Sensor Temperatura PT-100

The Si7021 is a low-cost, easy-to-use, highly accurate, digital humidity and temperature sensor. 

This package includes a Sensor of Level of Water and a Sensor of Humidity from Solo. If the plates have water covering the sensor components, an analog value will be available on the "SIG" connection. The Sensor of Level of Water can detect up to 4cm of water. This way, you can check if your aquarium, or your pet's water bowl, still has enough water. You can use the Sensor of Moisture of the Soil to check your plant's soil or growing environment, for example.

Temperature Sensor - Grove

A Whadda Universal Temperature Sensor Mounting Kit, used for measuring indoor and outdoor temperatures, controlling the rise/fall of temperature in homes, equipment, control of temperatures in some processes, visualization of the temperature on your website, control of the temperature of your pool, etc.

Detecting temperature changes has never been easier. The MCP9700 is a small thermistor type temperature sensor. 

Uses the NTC Thermistor Sensor, Good Sensitivity. The Clean Waveform of the Comparator Output Signal is Good, Driving Capacity.

DS18B20 is a single-bus digital temperature sensor with features of ultra-small size, wide range of applicable voltage and measurable temperature and high resolution.

SparkFun humidity sensor - HIH-4030

The kit does not require any soldering and is recommended for anyone with a drive to learn more about Blynk and its uses. So if you are looking for a new challenge or a way to get in on the IoT craze, check out the SparkFun IoT Starter Kit with Blynk Board!

The Atlas Scientific pH circuit designs currently available on the Internet are outdated and use a significant number of overly complex analog components. Atlas Scientific has reinvented and refined the pH circuit of the past to a more modern and simple to use model.

Sparkfun Temperature and Humidity Sensor- SHT15