Commands:

demo_pause demo_pause This useful console command is used to pause the demo you're watching. Playback can be resumed with the command demo_resume.
demo_resume demo_resume This useful command is used to resume the demo you're watching, if you have previously paused it. To pause demos, use the command demo_pause.
demo_timescale demo_timescale [Playback speed] This command sets how quickly the demo is played. In other words, it can be used to fast forward through rounds you're not interested in watching.
demo_togglepause demo_togglepause Use this command when watching demos to toggle between being paused or not. The good thing about this command is then it will pause or play the demo, depending on if its running when the command is entered.
demo_gototick demo_gototick [Tick] Forces the demo you're watching to skip to a certain tick.
demo_listhighlights demo_listhighlights This command produces a list of the highlights data extracted from the demo you're watching. Data will be pasted into your developer console.
demo_listimportantticks demo_listimportantticks Use this command for a list of the ticks that the game client determined to be important in a specific demo.
load load [Game Name] This command allows you to load a saved file. You can use this when you're not in multiplayer to bring up a demo file of yours or something similar.
demolist demolist Prints the demo sequence list in your developer console for you to see.
demos demos This command returns you to the homescreen of CS:GO, though in some cases it can crash your game .
listdemo listdemo When in a demo file, putting this command into your console will show you a list of the contents in this particular demo.
csgo_download_match csgo_download_match [Match ID] This command is used to download a CS:GO match, provided you know its unique serial code .
demo_recordcommands demo_recordcommands [0 / 1] This command records any commands typed into the console and saves them in a .dem file.
demoui demoui This command will toggle the visibility of the demo player UI. With the demo UI open, you can speed up and slow down demo playerback, skip rounds, etc.
endmovie endmovie This command will stop recording a movie that you have previously started recording with the startmovie command.
nextdemo nextdemo This command will make the next demo in your current demo sequence be played.
playdemo playdemo [Demo File Name] This command plays the specified demo file. Demos should be placed in your Steam\steamapps\common\Counter-Strike Global Offensive\csgo folder. If you place them in your "replays" folder, you need to specify "replays/" before the demo name.
record record [Demo File Name] This command will start recording your current game as a demo. You need to specify a filename to save the demo as. Use the "stop" command to stop recording. Demo will be saved in Steam\steamapps\common\Counter-Strike Global Offensive\csgo.
demo_goto demo_goto [Tick] [Relative (0 / 1)] [Pause (0 / 1)] This command skips to the specified tick in the demo. See argument information for options.
demo_info demo_info This command prints to console information about the demo that is currently playing.
editdemo editdemo [Name] This command may not work. It will edit the demo with the specified name (place the demo file in the "csgo" folder, the "csgo" folder is in the folder that csgo.exe is in).