Tool textures (Source)

The tools textures can easily be found in Hammer by running "tools" as a filter word in the texture browser. These textures have extra attributes that most textures do not.

Note: Here's a tutorial on using many of the Source Tool textures shown below [1]

Image	Name	Special attributes
	Area portal	Use with func_areaportals and func_areaportalwindows
	Black
	Block LOS	Blocks the line-of-sight of NPCs and bots
	Block bullets	Solid to bullets but not light or other objects.
	Block light	Invisible; casts shadow like standard materials
	Clip	Solid to all objects. Is not rendered.
	Player clip control
	Fog
	Hint	Divides visleafs.
	Invisible	Solid to all objects, invisible and does not cast shadows
	Ladder	Invisible; Use in Counter-Strike: Source with func_ladder.
	No Draw	Solid; Invisible; seals leaks; blocks visibility if used on all surfaces of the same brush
	NPC clip	Solid to NPCs but not players or other objects, is not rendered.
	Occluder	Use with func_occluders
	Origin	Use to set the rotation origin of rotating entities; obsolete in Source
	Player clip	Solid to players but not NPCs or other objects, is not rendered.
	Skip	Invisible; has no effect on anything.
	Skybox	Use to make 2D skyboxes. Casts light if there is a light_environment entity in the map.
	SkyFog
	Trigger	Use on Trigger entities and Buyzones in Counter-Strike: Source. Also don't forget to move the selected trigger brush(es) ToEntity so you can change the properties.