quicknade will quickly pull out a grenade, upon releasing the key the grenade is thrown and you switch back to your last weapon
quickgrav gives you a more "grab and throw" version of the pull out gravity gun script from vanilla HL2, this allows you to pull it out and immediately grab what your looking at no matter if your holding m2 or not, then once releasing the button, the held object is launched
quickmelee will let you grab your crowbar in close range combat at a faster speed, if a zombie is gaining up on you while you have a gravity gun out, the next thing they now they are already on the floor getting beat up by a crowbar
To use them, input these commands with the desired key
bind (desired key) "+quicknade"
bind (desired key) "+quickgrav"
bind (desired key) "+quickmelee"
these are only for MMOD because the gravity gun is bugged in vanilla half-life 2, but feel free to use the quick melee and quick grenade in the main game