Here is a list of all documented namespace variables with links to the namespaces they belong to:

A0 : arduino
A1 : arduino
A2 : arduino
A3 : arduino
A4 : arduino
A5 : arduino
ADC_FULL_SCALE_MILLIVOLTS : phyduino
EXT_ADC_FULL_SCALE_MILLIVOLTS : phyduino
HIGH : arduino
INPUT : arduino
INPUT_PULLDOWN : arduino
INPUT_PULLUP : arduino
led : phyduino
LED_BUILTIN : arduino
LOW : arduino
OUTPUT : arduino
PINS : phyduino