According to Combodef.lua, the combo names are:
Code:
7 shots pistol
Angry Farmer
Bar Tender (Barrel mid-air shot)
Barbecue
Bestial Lobotomy
Bestial Penetration
Bestial VampGun Mockery
Blood Burner
Bloody Necroannihilation
Boot Sector
Braindead
Brainsplatter
Burnout
Circus Stab
Demon01ShadowHandMelee4Times
Disaster For Innards
Double Stabber
Evil Seed
Fearbringer
FlamerAndSHmelee
Flying Duck
Godfinger
Grave Digger
Grenade Booster (Grenade mid-air shot)
HeadShot Machine Gun
Herr Doctor
Ice Duke
IceBallAndSHmelee
Impalement
Inhumator
Jiggle Bell
Lame Clipper
Lifeslaying Melter
Light in Tunnel (Lamp mid-air shot)
Mangle Wringer
Melee + Shotgun or Shovel
MeleeAnd2Shots
MeleeAndMeleeAndKick
Morbid VampShotgun Extermination
Penalty Kick
Performancer
Piercing
Pistol Headshot
Porcupine Destroyer
Porcupine Hater
Pure Fatality
Purification
Redneck Fury
Rifle Headshot
Roasted Hedgehog
Roller
Rush Hour
Russian Roulette
SHmeleeAndVampGun3shots
Shovel HeadCut
Shrapnel of Ice
Shredder
Soccer Faul
Soccer Star
Stab & Shoot
StakeAndSHMelee
Takedown
Termination
Throat Cutter
Triple Smasher
VampGun30Shots
Vampiric Shotgun Slaughter
VampShotgunAndSHMelee
As for how to trigger each one, well, I'm too lazy to dig that out. Note that some of them might have been disabled in the retail version.