Champion's Collection is an achievement in Diablo 3.
Kill a champion of all the following types[1]:
Horned Charger
Imp
Carrion Bat
Savage Fiend
Quill Demon
Scavenger
Returned Executioner
Skeletal Archer
Dark Berserker
Dark Hellion
Unholy Thrall
Disentombed Hulk
Hungry Corpse
Ravenous Dead
Fallen Overseer
Fallen
Fallen Peon
Fallen Cur
Fallen Conjurer
Accursed
Savage Flyer
Deathly Haunt
Grim Wraith
Vicious Ghoul
Lacuni Slasher
Rock Giant
Sand Behemoth
Sand Wasp
Reaper
Skeletal Raider
Bone Warrior
Spine Hewer
Skeletal Ranger
Chilling Construct
Shock Guardian
Noxious Guardian
Writhing Deceiver
Webspitter Spider
Brood Hatchling
Vile Swarm
Hulking Phasebeast
Demonic Tremor
Armored Destroyer
Herald of Pestilence
Demonic Hellflyer
Demon Trooper
Fallen Overlord
Fallen Slavelord
Fallen Grunt
Fallen Soldier
Fallen Mongrel
Fallen Hellhound
Blood Clan Warrior
Blood Clan Mauler
Blood Clan Impaler
Blood Clan Sorcerer
Blood Clan Occultist
Wintersbane Huntress
Stygian Crawler
Icy Quillback
Skeletal Marauder
Skull Cleaver
Dark Skeletal Bowman
Soul Ripper
Succubus
Plague Swarm
Darksky Fire Demon
Enslaved Nightmaare
Mallet Lord
Subjugator
Morlu Legionnaire
Morlu Incinerator