Quality Thermistor Inc.
Manufactures through hole and SMD NTC and PTC thermistors, thermistor beads and probes, temperature probes and thermistor probes. Online catalogue, application notes and purchasing.
http://www.thermistor.com/

General Measurements
Leading Designer and Manufacturer of Process heaters and temperature sensors. Heating elements, electric heaters, thermocouples, RTDs, thermistors, and cartridge thermostats, and thermal systems.
http://www.generalmeasurements.com/

Connect2it, LLC
Spring probes, pogo probes BGA, PGA, LGA probes and fine interconnects, conductive elastomers, micro test clips, switch probes, automotive probes, automation test systems and pin loaders. (Pop-ups and consoles too)
http://www.connect2it.com/

Pomona Electronics
Whether you test in a lab, the plant, or the field, your success depends as much on your choice of test accessories as it does on the accuracy of your instruments. That's why professionals over the world put their trust in Pomona. From test leads and probes, to kits, adapters, and IC test clips, Pomona products offer you the performance and dependability your job demands.
http://www.pomonaelectronics.com

ECH2O Soil Moisture Probes
Decagon Devices provides accurate and reliable soil moisture sensors with applications in agriculture, greenhouses, and research.
http://www.ech2o.com

YSI
Designs, manufactures and distributes water quality and environmental monitoring equipment, temperature probes, temperature measurement equipment, thermistors, CO2 sensors, glucose analyzers, and lactate analyzers.
http://www.ysi.com

Exacon Scientific A/S
Medical Temperature probes - Medical temperature sensors - Medical Thermistor Probes - Medical Thermistor Sensors from EXACON SCIENTIFIC.
http://www.exacon.com/

Advanced Thermal Products
manufactures temperature-sensing probes and assemblies and PTC and NTC thermistors.
http://www.atpsensor.com/

United Sensor Corporation
Offers a wide variety of temperature and pressure sensing probes.
http://www.unitedsensorcorp.com

U.S. Sensor Corporation
U.S. Sensor manufactures precision thermistors, thermistor probes and thermistor assemblies for temperature measurement, control and compensation applications.
http://www.ussensor.com/