Lone Shotgun Hunter
Singleplayer
Combat shotgun (spas) and baseball bat as weapons.
Hunters and Jockeys for special infected, only one can spawn at a time.
Up to 12 common infected.
Console command: map mapname lone_shotgun_hunter

Shotgun Hunters
Multiplayer
Combat shotgun (spas) and baseball bat as weapons.
Hunters and Jockeys as special infected. Up to two special infected can spawn. There could be two hunters, two jockeys, or one hunter and one jockey.
Up to 12 common infected.
Console command: map mapname shotgun_hunters