1st method
1:Start the game
2: go to options
3: click on keyboard layout
4: click on advanced
5: click on enable developer console
6: You should be able to open the console now by pressing the button below the "escape button' on your keyboard
(if the 1st method doesn't work, you can always try the 2nd one)
2nd method (most complicated and for advanced console users)
1: click once on the no more room in hell game
2: Right click on it
3: go to properties
4: type -console
5: load up ur game
6: bind a key to your console in the console menu so it doesn't disappear from time to time
(can be annoying while typing, you're warned)
example: bind p toggleconsole (you can use any key you want but don't use common characters for typing such as e,o,n, ...)


sv_cheats <0/1>
Toggles the cheats variable on or off default is 0 (off). example: sv_cheats 1
NOTE: granting sv_cheats 1 to the console gives the ability for ALL players to use the following commands.

To replenish ammo use: givecurrentammo
Type give with for example: give fa_1911 (Sv Cheats 1)
Weapon Classnames (Grouped by Category)
any
firearm
handgun
fa_1911
fa_glock17
fa_mkii
fa_sw686
fa_m92fs
rifle
fa_1022
fa_cz858
fa_sako85, give fa_sako85_ironsights, giva fa_fnfal
fa_jae700
fa_sks, fa_sks_nobayo
shotgun
fa_500a
fa_870
fa_superx3
fa_sv10
fa_winchester1892
machinegun
fa_mac10
military
fa_mp5a3
fa_m16a4, fa_m16a4_
archery
bow_deerhunter
me_axe_fire
me_bat_metal
me_chainsaw, me _abrasivesaw
me_crowbar
me_etool
me_fubar
me_hatchet
me_kitknife
me_machete
me_pipe_lead
me_shovel
me_sledge
me_wrench
explosive
exp_grenade
exp_molotov
exp_tnt
items
tool_barricade
tool_extinguisher
tool_welder
tool_flare_gun
item_bandages
item_first_aid
item_maglite
item_pills, item_gene_therapy
item_walkietalkie
ammo (Does not work use givecurrentammo instead)
ammobox_9mm
ammobox_45acp
ammobox_357
ammobox_12gauge
ammobox_22lr
ammobox_308
ammobox_556
ammobox_762mm
ammobox_arrow
ammobox_flare
ammobox_board
ammobox_fuel

sv_infection_chance 0 (changes infection chance so you cannot get infected)
sv_infectionlength 90000 (you can have any number, I put 90k because it's pretty long)
sv_idle_autokick_enabled 0 (No more random kicking from your own server)
sv_kills_per_token 1 (This changes how many kills you need before you get a respawn token in extinction)
sv_zombie_health 100 (obviously changes zombie health)
sv_health_station_health 800 (changes the first aid box in survival mode to different amounts. 800 is just an example, you can have any number)
sv_gravity # Set Gravity (Add number in place of #)
sv_soundemitter_filecheck Toggle reporting missing .wav files for sounds
sv_lan <0/1> - When set to 1, launches the game in LAN mode. Useful to stop players from joining your game from the Internet.

fov (experiment with these numbers if you want)
firstperson - Play in first person
thirdperson - Play in third person

cam_idealpitch # (Leave at 0 or the crosshair won't match the shooting direction)
cam_idealyaw # (Same as above)
cam_collision # (Whether the camera collides with walls so as not to see through them.)
cam_ideallag # (How much the camera waits before moving after the mouse is moved. Best leave it at 0.)
cam_idealdelta #
c_thirdpersonshoulderdist #
c_thirdpersonshoulderaimdist # (Which distance the crosshair will be aligned at to shoot.)
c_thirdpersonshoulderoffset # (How much to the left or to the right the camera is.)
c_thirdpersonshoulderheight # (Similar to above only it controls height instead.)
c_thirdpersonshouldersnapto # (Best is 1.)

buddha 1 (you'll get less damage but you won't be invincible -> better to use sv_zombie_dmg_x 0 and sv_zombie_reach 0 / ai_disable)
god 0 - 1
Only objects effected by physics are wireframe: vcollide_wireframe 1
Draw game triggers: showtriggers_toggle
map (name) - loads up a map
cl_ragdoll_collide 1 Enables ragdolls that don't clip through each other, but stack realistically on one another. (no cheats needed)
cl_showfps 1 Shows FPS Rate (no cheats needed)
cl_showpos 1 brings up position display in top right of screen (0 removes it) (no cheats needed)
Developer # Sets developer mode to on/off/verbose (0-off, 1-on, 2-verbose)
exec # Execute a script file (Input filename in place of #)
getpos can be used to get current coords for use with setpos
help $ replace $ with a command to get a brief description of it
Hurtme # Damages player by whatever variable you input as #

Kill You die.
Explode You die but in a more fashionable way
maps Displays Map listing
net_graph 1 a more thorough fps display
noclip Ability to walk through walls (Server Side Only)

picker Toggles Picker mode on
prop_debug Toggle bounding-boxes debug mode on/off red - ignore damage, white - respond to damage, green - health)
setang Snap players eyes to a specified pitch yaw
setpos Move player to specified origin
skill # change skill level (# = 1, 2, or 3)
status shows some game info, incl. current map
cl_richpresence 0 (default = 1) Disable discord rich presence

viewmodel_fov # Adjusts size of the weapon you're carrying (54 = default)
"bind (any letter or number) *enter phrase*"

cl_showfps <0/1/2/3> -- When set to 2, shows the framerate and map name.
fps_max # (you have to set this before playing a game, don't put it to high, don't put it to low)

...
only crawlers, kids, runners
sv_zombie_shambler_crawler_chance 1
sv_max_runner_chance 0.6 (default setting) Change the next three down to zero for no runners.
ov_runner_chance 0.075 (default setting) Change to 0
ov_runner_kid_chance 0.5 (default setting)

ai_disable 0 (to let them move)

npc_create npc_nmrih_shamblerzombie
npc_create npc_nmrih_runnerzombie
npc_create npc_nmrih_kidzombie
npc_create npc_nmrih_crawlerzombie (not sure if this works)
npc_create_aimed npc_nmrih_shamblerzombie (Creates an NPCAiming away from player)

impulse 203 removes the item or NPC pointed at

sv_zombie_health 0 - whatever number you want, (just experiment with the others by using the sv_zombie_)
0 gives immediate kill with whatever dmg source ur hitting

If you need to kick a player replace name with the players name. | example: kick hoarder
This command can be used in a number of ways. example: | kick <name>, kick <IP>, kick <steamID>
status: shows ips
banid <time>
If you need to ban a player replace time with the amount of time you would like to ban them. Enter 0 for a perma-ban. | example: banid 0 STEAM_0:0:123456
addid < minutes> < ipadress>
sv_password <password>
Sets the server password so only players who know the password can join the server. If this is a public server this is not recommended. | example: sv_password thisispassword
mp_friendlyfire <0/1>
(check mp_ with all the alphabet characters written behind it)
Toggles the map friendly fire variable on or off default is 0 (off). | example: mp_friendlyfire 1
say <text>
Sends a message from the server admin to the screen which all players can read. replace text with the message. example: | say Server restart in 5 mins
quit
Self explanatory -Shuts down the server

r_drawclipbrushes 0 1 2 3 4
r_drawviewmodel 0 1 (if you want great screenshots)
r_3dsky 0 1 (default is 1)
r_drawbeams 0 1 (spotlights dust effect disappear if set on 0
r_draw...
r_screenoverlay effects/combine_binocoverlay.vmt Gives you combine vision during gameplay.
r_screenoverlay effects/tp_eyefx/tp_eyefx.vmt Gives you weird vision during gameplay.
r_screenoverlay normal (sets it back to normal)
full list of screenoverlays:
https://developer.valvesoftware.com/wiki/Env_screenoverlay

hud_say_Textime 0 (hides public chat, no sv_Cheats required)

con_filter_text_out (word) example: con_filter_text_out vertex
con_Filter_enable 0 1 (i believe this is 1 by default since i can do this freely)

https://developer.valvesoftware.com/wiki/Command_Line_Options
https://developer.valvesoftware.com/wiki/
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?l=dutch&id=192742189
http://www.nomoreroominhell.com/forums/index.php?showtopic=11571
http://dota2.gamepedia.com/List_of_Console_Commands
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=197862101
https://developer.valvesoftware.com/wiki/List_of_DOTA_2_Cvars
Basically this is a complete list from A to Z for Dota 2 only (be warned)
http://dota2.gamepedia.com/List_of_Console_Commands

Set Launch options:

https://support.steampowered.com/kb_article.php?ref=1040-JWMT-2947&l=dutch
https://developer.valvesoftware.com/wiki/Command_Line_Options#Steam_.28Windows.29