Thermistors and RTDs (Resistance Temperature Detectors) are both forms of resistors used for measuring temperature.
The main difference between them is the material they are made from. An RTD is made from pure metal whereas a Thermistor is made from polymer or ceramic material.
The RTDs therefore measure over a much wider temperature range (up to 650 degrees Celsius) but the Thermistors are more accurate (up to +/-0.05 degrees Celsius).
We have devices aimed specifically at RTD-to-Digital Conversion ( MAX31865 ) and devices aimed at Thermistor-to-Digital Conversion ( MAX6682 / MAX6691 ).