a thermocouple would also be able to be connected.
anything that uses 5 volts or less would also be able to be connected to a digital out and ground line. i have a buzzer hooked up to one of the digital outs on my iobridge.
you can activate momentary buttons by soldering wires to the button and using a digital output pulse.
also, pwm cables have the correct spacing for connecting to the iobridge