The Screamer
Health - Unknown, likely low so it could be quieted easily after sounding off
Abilities - Running off to scream, sending a horde after Survivors
Attacks - None
The Charger
Health - 500+
Abilities - Charges Survivors until knocked down
Attacks - Charging, slamming Survivors while down, grabbing Survivors
The Spitter
Health - Unknown
Abilities - Ranged area-of-effect acid attack, Full Vision
Attacks - Spitting, Clawing
The Hazmat-suited Infected
The Hazmat-suited Infected appear exclusively in the Left 4 Dead 2 campaign, The Parish. Players will occasionally come across Common Infected wearing a Hazmat Suit, which was likely being worn prior to the person being infected.
Though not as numerous as normal Common Infected, they share the same health, abilities and weaknesses. However, due to their Hazmat Suits, they are immune to fire in all forms.
This includes:
Incendiary Ammo
Static Fire (e.g. Burning barrels)
The Mud Men
The Mud Men will appear in the campaign Swamp Fever. They are similar to the Common Infected in most ways, except that they are covered in mud and use this as camouflage. They sprint on all fours. However, if it is shoved, it will go back on to two feet, the same way the Hunter does. They also run even faster than regular Infected. This makes them particularly harder and annoying to kill, especially when traversing through water as they can run below water as their own ground, while Survivors are slowed when inside the water. When a Mud Man hits you, your screen is partially covered in little mud; the more it hits you, more mud covers your screen.
The reason why they walk on all fours could be that it's hard to get around in the mud using just their legs, so to help them traverse, they adapted by using all four limbs to move.Or it could be an infected half way turned into a Hunter.
Riot Infected
Chet Faliszek stated in an e-mail that "The Parish" would gain another Uncommon Infected; the Riot Infected. While human, they were members of a private security firm, which was hired by CEDA to protect civilians. In laymen terms: they were "Rent-A-Riot-Cops". However they were Infected while wearing their gear, and the Kevlar gives them immunity to bullets. Chet has stated however, that they will not be immune to fire, melee weapons, or explosives.
Credit: To Joltener for finding Info and picture's.
