Here is a list of all namespace variables with links to the namespace documentation for each variable:

AxisCount : sf::Joystick
BlendAdd : sf
BlendAlpha : sf
BlendMax : sf
BlendMin : sf
BlendMultiply : sf
BlendNone : sf
ButtonCount : sf::Joystick, sf::Mouse
Count : sf::Joystick, sf::Sensor
KeyCount : sf::Keyboard
ScancodeCount : sf::Keyboard