I've looked into the GECK to find some information about the special attacks. They are a property of the weapon, so there is no nice overview.

The Back Slash has an AP cost of 16 (with a knife) and a DamageMultiplier of 0.7 and is silent.

The Grand Slam (found on the baseball bat) uses 35 AP (compared to 25 standard) and deals 2x damage and is silent

The Long Cut for the Ripper has an AP cost of 70 (compared to 65) and deals 1.2x damage and is silent.

The Scrap Heap for the Thermic Lance has an AP cost of 70 (compared to 65) and deals 1.25x damage and is silent.

There could be some more scripts attached to this special moves, but I did not find them.

I've looked into the GECK to find some information about the special attacks. They are a property of the weapon, so there is no nice overview. The AP costs vary per weapon, the other effects not, as far as I can see.

The Back Slash on a knife has an AP cost of 16 (with a knife) and deals 0.7x damage.

The Grand Slam on the baseball bat uses 35 AP, compared to 25 standard, and deals 2x damage.

The Long Cut for the Ripper has an AP cost of 70, compared to 65 standard, and deals 1.2x damage.

The Scrap Heap for the Thermic Lance has an AP cost of 70, compared to 65 standard, and deals 1.25x damage.

The Mauler for Super Sledge has an AP cost of 48, compared to 38 standard, and deals 50% damage. This attack knocks down the enemy (if Stonewall perk is not present).

The Lights Out for Police baton has an AP cost of 29, compared to 23 normal, and deals 1.25x damage.