p_facing_ratio - computes the difference between the normal and the eye ray and creates a gradient for this value. Can be used to fake a fresnel effect etc.
p_color_plus_alpha - merge color and alpha. Can be used to add transparency to any shader. Can also be used to mix Maya shaders and mental ray shaders to solve problems with alpha.
p_motion_to_rgb - surface shader to convert motion vectors to RGB to create a motion blur effect during compositing.
p_irradiance - surface shader to compute irradiance (FG, GI and Caustic). Can be used to output the irradiance color in a separate pass for later compositing. This shader can also be used with a common shading network to tune up the irradiance color.
p_color_to_float - convert color to float, supports several types of conversion: R, G, B, A, Average, Luminosity. The shader returns a float.
p_saturation - change saturation of color
p_fisheye - lens shader, create fisheye effect.
p_buffer_writer - surface shader for rendering objects with multiple passes.
p_z - surface shader to compute the z channel with sampling. Supports 8, 16 and 32(float) bits per component. Alpha is supported.
p_ray_type - surface shader for rendering object with different shaders depending on ray type.
p_shadow - surface shader for rendering shadow only without shading.
p_bake_read - texture shader, assign different textures depending on object name.
p_MegaTK - universal surface shader for splitting out many passes in one render.
p_environment - shader for computing Environment Reflection or for computing ambient light from environment for Baked Occlusion.
p_shadow_transparency - shadow shader for computing colored and transparent shadows with attenuation and edginess effect.
p_scatter_wrap - shader for faking scattering effect (based on object thickness) and additional wrap effect. The shader returns a float.

local backup: puppet/shaders_p_3.3_xsi_win.zip