There is 1 Super rare infected, Named jimmy gibs jr.
He is only findable in Dead center finale, and here is the picture

Copied from the L4D Wiki:
"If the laws of nature allowed it, I would bear that man's children."
—Ellis
Jimmy Gibbs Junior is a "famous" racecar driver from the South and considered an idol in the eyes of Ellis and Coach. He is dressed in his racing suit and only spawns in the Atrium, with a 5% chance of spawning at all. He is mentioned by the Survivors briefly, saying things such as "If we see him, someone else is going to have to kill him". This may be another play on the remake of the movie Dawn of the Dead, where the Survivors could see Infected versions of famous people that they knew from the mall. He has 1000 HP, no detachable limbs, can blind the player with motor oil (similar to the Mud Men's splatter effect) is not drawn to pipe or bile-bombs and thanks to his racing suit, is nearly fireproof. He, like every other Infected, can be spawned using a console command.
New infected: The fallen survivor


These guys dont attack, but run away, if they die, you can take there molotov, medkit, and the new weapons that are coming out
Copied from L4D wiki:
The Fallen Survivor was evidently a fairly well-equipped Survivor from the initial outbreak, but unfortunately became Infected later on. He wears militia attire including a boonie cover and three ammo belts with a strap carrying visible molotov, pipe bomb and pills. He also has a first aid kit and a magnum pistol in a holster strapped to his right thigh. His original ability was that he would immediately ignite if shot, due to the molotov that he is carrying and deal large amounts of damage to the Survivor. Melee weapons were useless against him because they also would ignite the molotov. He might have also dropped First Aid Kits that you could actually put into your fourth slot.
There is a possibility of him being cut due to his ability being extremely dangerous to the Survivors as well as the Infected . He can be seen here, with mods. Interestingly enough, his character model is nearly identical to that of Whitaker. He can also be seen briefly in the "Zombie Survival Guide", running towards the Survivors in The Plantation. He can also be spawned by a console command.
He is set to appear in the upcoming campaign "The Passing". His new behavior has him running from Survivors much like The Screamer, to avoid getting shot, thus making him the least threatening Infected. However he can be equipped with any weapon, healing agent, or grenade imaginable thus making him a value to the players if they want a certain gun or are low on health.
Fallen survivor was cut from l4d1 and is here now