Impulse

The advantage is that new commands can be added without compatibility-breaking networking changes; the disadvantage is that only one impulse can be sent at a time, and that the commands themselves are non-descriptive.

Impulse commands are generally used for development functions and/or cheats, and almost all require sv_cheats.

Impulses

General

These are available in most or all Source games.

#	Notes	Description
81		Gives the player the weapon_cubemap, used to test cubemaps.
100	Not a cheat	Toggle the player flashlight. Might require item_suit, depending on the game. Bound to F by default.
101		Gives player full health, all weapons, and ammo.
102		Spawns a VPhysics human skull (models\Gibs\AGIBS.mdl) from inside the player (might land behind you). Meant to spawn a "random" gib and seems to be used in Half-Life: Source.
103		Prints AI state of the NPC the player is looking at to the console. Requires developer mode.
106		Prints the class, targetname and model of the entity under the crosshairs to the console.
107		Prints the material that player is looking at to console. Only works on brushes: use mat_crosshair instead, which works on displacements too.
108		Sets the NPC under the crosshairs as the Debug NPC. Doesn't appear to have any effect?
195 196 197	Nonfunctional	Supposed to show the shortest path to the nearest air, large, and human nodes respectively.
200		Plays the current viewmodel's holster animation. Doesn't actually prevent attacking. (The current weapon just won't be visible.) Not all weapons have holstering sequences.
201	Not a cheat	Creates a player spray on the brush under the crosshair. Use Options > Multiplayer to set a spray. Default key is T.
202	Obsolete	Spray blood over the brush under the crosshair.
202	Not a cheat	Plays a "player jingle" soundfile. To enable jingles, set cl_soundfile to a WAV file under 128KB, enable cl_customsounds and join a server. Jingles go through the same system as sprays, and are subject to the same anti-spam cooldown.This works with the SDK codebase, but games typically appear to disable jingles.
203		Remove the entity under the crosshairs. Same as ent_remove.

Half-Life

#	Notes	Description
76		Spawn a human grunt 128 units in front of you. A restart may be needed.
104		Dump the global entities or state variables. These variables indicate if, for example, the electric generator in Blast Pit is on

Half-Life 2

#	Notes	Description
50	Not a cheat	Makes player command (call/send) a squad. Default key: C
51		Spawns item_dynamic_resupply.
52		Rangefinder. Prints Starting position, ending position, 3D distance and 2D distance.
82		Spawns an armed jeep.
83		Spawns an airboat.