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

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.

Temperature Sensor - Grove

Electronic Brick - Soil moisture sensor is mainly used to detect soil moisture content . The module can obtain the soil moisture value or limit through analog or digital pins.

The Earth Unit is a Sensor for measuring Humidity in Soil or Similar Materials. The Soil Moisture Sensor is quite simple to use. The two large stake-type sensors act as probes for the sensor, acting together as a variable resistance. The higher the moisture in the soil, the better the conductivity between the two, so that the sensor results in less resistance and higher GIS output.

You can read the moisture in the soil through ADC. Within this unit, there is an extra potentiometer to change the measurement range.

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.

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

Sensor Temperatura PT-100

Grove's capacitive humidity sensor (corrosion resistant) is a soil moisture sensor based on changes in capacitance. Compared to resistive sensors, capacitive sensors do not require direct exposure of metal electrodes, which can significantly reduce electrode erosion.