1) Go to the Steam library page of your Source Engine game, click on the gear icon > Properties... and under the LAUNCH OPTIONS section, paste this:

-console -condebug

-console: Launches the game with the console.
-condebug (console debug): Prints the console output in the console.log file.



2) Launch your game. In the main menu, paste the following in the console and hit Enter:

cvarlist

Note: If the console doesn't appear, maybe the -console param is not working properly in your game. Try enabling the console going to Options > Keyboard > Advanced and check "Enable Developer Console". Now start a match or a level and hit the tilde (~) key.

3) Now go back to your Steam client, click on the gear icon again > Manage > Browse local files.
4) In the search bar from the right side, type console.



5) Copy that file to your desktop and open it with any text file editor.
6) There is a bit of trash at beginning, you can go ahead and delete it. Press Ctrl + F to search an specific command, or keywords which you think describe the command you are looking for. Invulnerable, bot, stop, flies, time, life, ammo, item, etc.

The -condebug launch parameter doesn't work with the cvarlist command as you can see here. Some workarounds could be:

A) Using this command instead:

cvarlist log cvarlist

Which the output is a bit ugly but it works I guess. Now you must look for a file called cvarlist instead console.log and change its extension to .txt.

B) Use these commands and manually copy their output one by one to a text file.

Cvarlist -
Cvarlist _
Cvarlist A
Cvarlist B
Cvarlist C
Cvarlist