Ok, so I got a list of sensors that will be supported in the rules UI in the next firmware release.
It should make things a good bit more usable than it is now, as it includes most of the sensor types we're supporting, but maybe not everything.
BinarySwitch
MultilevelSwitch
BinarySensor
MultilevelSwitchOnOff
DoorLock
Thermostat
StandardCIE
MotionSensor
ContactSwitch
FireSensor
WaterSensor
GasSensor
VibrationOrMovementSensor
KeyFob
SmartACSwitch
FloodSensor
DoorSensor
Siren
BinaryPowerSwitch
SecurifiSmartSwitch
There might be more additions before that release is out, but I just want to show that we're working on adding more things and that progress is being made.