Now with group auto-spawners!
This addon allows you to spawn groups of NPCs from the NPC tab, under the category "Groups". If you find youself spamming the "Combine Soldier" button or "Citizen" or whatever, this may make it easier on you.

Changes/additions in V.5:
* NPC Group Spawners: The point of NPCG was to make NPC spawning easy. As someone pointed out, it would be even easier if the spawning was done automatically. So here we are.
* NPCG Spawners will replace any NPC killed after half-a-second. If you kill the shotgun-wielder, a new shotgun-wielder will spawn in his place.
* Battlefield management: If "Keep Corpses" is on, then you can have ragdolls disappear after a set amount of time. This is managed by the console command "npcg_ragdoll_lifetime", 20 seconds by default.

New Groups:
Category: "Groups - Spawners"
* Antlion spawner (Antlion pack)
* Combine spawner (Combine Fireteam)
* Police spawner (Police Squad)
* Rebel spawner (Rebel Group)
* Zombie spawner (Zombie Group)
* Zombine spawner (Zombine Strays)

New console command:
* npcg_ragdoll_lifetime - Controls how long corpses stick around if "Keep Corpses" is on.
All old console commands are still here. Reference them in Command reference.txt if you want to.

Custom model groups make a glorious return.
* npcg_custom_model_combine sets the Combine group's model.
* npcg_custom_model_rebel sets the rebel group's model.

Thanks to everyone who provided suggestions for this release.
Enjoy!

Note that in the screenshots above, the battles were constructed by spawning only two entities. NPC Groups does the rest.
Still looking for suggestions for new features, post your ideas below!