Six that i can think of: 1. Thermocouples. 2. Resistive temperature devices. (RTD's and thermistors) 3. infrared radiators. 4. Bimetallic devices. 5. liquid expansion devices. (thermometer) 6. Change of state devices.
The most common scales of temperature are:
Celsius (°C)
Kelvin (K)
Fahrenheit (°F)
Rankine (°R or °Ra)
Other scales of temperature include:
Delisle (°De)
Newton (°N)
Réaumur...