gearbox (Opposing Force)
valve (Half-Life 1)
dmc (Death Match Classic)
ricochet (Ricochet)
tfc (Team Fortress Classic)
cstrike (Counter Strike)
holywars (https://www.moddb.com/mods/holy-wars/downloads/holy-wars-beta-20)
wizardwars_beta (https://www.moddb.com/mods/wizard-wars/downloads/wizard-wars-public-beta-130)
(These are not direct download links)

Simply, drag and drop the folder and replace the existing files.
Simple as that, your bots are now ready and will spawn automatically once you get into a game.

Ex:

Take "valve" folder and drop it into your "Half-Life" folder.
Replace the existing files and thats it.


///////////
/IMPORTANT/
///////////
While Metamod installed, you cannot play Offline, your saves will be corrupted so backup your saved single player games if you have any.
------------------------------------------------
Bots will be mixed with Jk_botti and HPB_Bot bots.

;;;;;;;;;;;;;
;Plugin list;
;;;;;;;;;;;;;


#################
#Monster Plugin #
#HPB Bot        #   
#Jk_botti       #
#AmxModx        #
#################

How to disable plugins and metamod mods ?

GO TO Half-Life/valve/addons/metamod/plugins (for any gamemode)
(The file path for other gamemodes are same as Half-Life)

Delete the line or put // on front of the mods.
Lets say, you want to disable monster mod that adds monsters, simply add // to disable it or delete it.
So it should look like this:

// addons\monster_plugin\monster_mm.dll

How to delete AmxModx plugins ? I don't want shiny weapons!

Go to addons/amxmodx/plugins

/////////////////////////////////////////
The plugins I installed for general use:
/////////////////////////////////////////

Cheat (Allows no clip and god mode on multiplayer)
HL_GiveWeapons (Allows you to give yourself or others weapons without sv_cheats)
country_on_name (Newly joined players will get tags depending on their country) (Disabled)
GHW_connect (Basically when someone joins or leaves it types it on chat with their country and steam name)
Antisg (Prevents tau cannon to hit you back)

To remove any existing plugins:

Go to:

addons/amxmodx/config/plugins
And delete the line that enables the plugin.
Or simply add // on the beggining of the line.
If you do that, the plugin will not be enabled. If you don't want to delete it you can also do that.