Within the console you have the ability to do a lot of things. To open the console hit the ` button.

Player Related Commands:

-BEHINDVIEW 0
First person view
-BEHINDVIEW 1
Third person view
-FREECAMERA 1/0
Locks player rotation (still allowing for 'WSAD' movement) and allows rotation around player.
-FOV xx
Change your current Field of View to xx degrees
-SUICIDE
Kill yourself

Recording Commands:

-DEMOPLAY demoname
Plays the specified demo demoname
-DEMOREC demoname
Records a demo as demoname
-STOPDEMO
Stops recording of a demo

Statistics Commands:

-MEMSTAT
Displays Windows memory usage
-STAT ALL
Displays all statistics
-STAT AUDIO
Displays audio statistics
-STAT FPS
Displays current and average frames per second
-STAT GAME
Displays game statistics
-STAT HARDWARE
Displays hardware statistics
-STAT NET
Displays network statistics
-STAT NONE
Turns off all statistics
-STAT RENDER
Displays rendering statistics

Miscellaneous Commands:

-DISCONNECT
Disconnects from current server
-EXIT
Quits the game
-OPEN ipaddress
Connects to the server at ipaddress
-PREFERENCES
Opens the preferences window in Windows
-RECONNECT
Reconnects to current server
-REPORT
Copies game info to the clipboard
-SHOWLOG
Opens the game log in Windows

Rendering Tweaks Commands:
Only For Solo Mode


-REND BLEND
Renders normally with mesh overlay
-REND BONE
Renders bones
-RMODE 1
Wireframe only
-RMODE 2
Zone view
-RMODE 3
Use textures
-RMODE 4
Turns all BSP white. Normal lighting for statics.
-RMODE 5
Normal rendering
-RMODE 6
No shadows
-RMODE 7
Lighting mode
-RMODE 8
Visualizing overdraw mode

Cheats Commands:
"enablecheats" Must Be Typed In for These To Work


-ALLAMMO
999 ammo for every weapon
-ENABLECHEATS
Enables cheats. Disables perk leveling.
-FLY
Enables flying
-GHOST
Noclip mode
-GOD
God mode
-LOADED
Gives all weapons
-PLAYERSONLY
Freezes everything except players
-TELEPORT
Teleports you to where you're aiming
-WALK
Disables flying and/or noclip mode

Admin Commands:

-ADMINLOGIN password
Logs you in as admin using password
-ADMIN ADMINSAY message
Displays message in middle of all players' screen
-ADMIN MAP KF-mapname.c0m
Changes current map to KF-mapname.c0m (the 0's should be o's)
-ADMIN SET ENGINE.GAMEINFO GAMEDIFFICULTY x
Changes difficulty of next map to x (1 = Beginner, 2 = Normal, 3 = Skilled, 4 = Hard, 5 = Suicidal)
-PAUSE
Pauses the game


That's all of them .. I made a cheat thread as well, I don't really think that's the same thing because they contain different stuff. @TheGodfather please look at it.


Credits:
-ME
-KF-Wiki