Here is a list of every kill & achievement that we have recorded along with screenshots and movies.
Vanilla WoW Kills ---
07/29/2006 Ossirian [screenshot]
08/03/2006 Onyxia [screenshot]
10/02/2006 Nefarian [screenshot]
10/04/2006 Thunderaan [screenshot]
Burning Crusade Tier 4 Kills ---
02/10/2007 Opera House [screenshot]
02/10/2007 Curator [screenshot]
02/11/2007 Terestian Illhoof [screenshot]
02/17/2007 Shade of Aran [screenshot]
02/17/2007 Prince Malchezaar [screenshot]
03/11/2007 High King Maulgar [screenshot]
03/14/2007 Nightbane [screenshot]
03/21/2007 Netherspite [screenshot]
03/22/2007 Gruul the Dragonkiller [screenshot]
04/29/2007 Doomwalker [screenshot]
05/01/2007 Magtheridon [screenshot]
Burning Crusade Tier 5 Kills ---
05/29/2007 Hydross the Unstable [screenshot]
05/31/2007 Fathom-Lord Karathress [screenshot]
06/04/2007 Morogrim Tidewalker [screenshot]
06/13/2007 Leotheras the Blind [screenshot]
06/14/2007 The Lurker Below [screenshot]
06/19/2007 Void Reaver [screenshot]
06/28/2007 A'lar [screenshot]
07/12/2007 High Astromancer Solarian [screenshot]
07/22/2007 Lady Vashj [screenshot] [movie]
08/20/2007 Kael'thas Sunstrider [screenshot] [movie]
Burning Crusade Tier 6 Kills ---
08/21/2007 Rage Winterchill [screenshot]
08/30/2007 High Warlord Naj'entus [screenshot]
08/23/2007 Anetheron [screenshot]
09/02/2007 Supremus [screenshot]
09/03/2007 Shade of Akama [screenshot]
09/09/2007 Kaz'rogal [screenshot]
09/12/2007 Azgalor [screenshot]
09/13/2007 Archimonde [screenshot]
09/16/2007 Teron Gorefiend [screenshot] [movie]
09/16/2007 Gurtogg Bloodboil [screenshot]
09/30/2007 Reliquary of Souls [screenshot]
10/14/2007 Mother Shahraz [screenshot]
10/15/2007 The Illidari Council [screenshot]
10/28/2007 Illidan Stormrage [screenshot] [movie 1] [movie 2]
11/13/2007 Zul'jin [screenshot]
Burning Crusade Tier 6.5 Kills ---
03/26/2008 Kalecgos [screenshot]
03/31/2008 Brutallus [screenshot] [movie]
04/14/2008 Felmyst [screenshot] [movie]
04/28/2008 Eredar Twins [screenshot] [movie]
07/28/2008 M'uru [screenshot] [movie]
09/15/2008 Kil'jaeden [screenshot] [movie]
WoTLK Tier 7 Achievements ---
11/19/2008 Sapphiron 10 [screenshot]
11/23/2008 Sapphiron 25 [screenshot ui]
11/19/2008 Kel'thuzad 10 [screenshot] [screenshot ui]
11/23/2008 Kel'thuzad 25 [screenshot] [screenshot ui]
11/29/2008 Malygos 10
11/24/2008 Malygos 25 [screenshot] [screenshot ui]
01/06/2009 Sartharion + 3 Drakes 10 [movie]
12/12/2008 Sartharion + 3 Drakes 25
01/18/2009 Naxxramas 10 Undying
03/25/2009 Naxxramas 25 Immortal [screenshot]
WoTLK Tier 8 (Normal) Kills & Achievements ---
04/15/2009 Emalon 10
05/30/2009 Flame Leviathan 10 (4-Tower)
04/14/2009 Razorscale 10
04/14/2009 Ignis 10
04/15/2009 XT-002 Deconstructor 10
05/17/2009 XT-002 Deconstructor 10 (Heart-Broken)
04/15/2009 Assembly of Iron 10 [screenshot]
04/16/2009 Assembly of Iron 10 (Steelbreaker Last)
04/16/2009 Kologarn 10
04/16/2009 Auriaya 10 [screenshot]
04/16/2009 Freya 10 (0-Elder) [screenshot]
04/16/2009 Freya 10 (1-Elder)
04/28/2009 Freya 10 (2-Elder)
05/23/2009 Freya 10 (3-Elder)
04/16/2009 Thorim 10 [screenshot]
04/25/2009 Thorim 10 (Sif Present)
04/17/2009 Hodir 10 [screenshot]
05/09/2009 Hodir 10 (3-Minute)
04/17/2009 Mimiron 10
06/13/2009 Mimiron 10 (Self-Destruct Button)
04/17/2009 General Vezax 10
05/19/2009 General Vezax 10 (No Saronite)
04/17/2009 Yogg-Saron 10 (4-Keeper) [screenshot]
05/03/2009 Yogg-Saron 10 (3-Keeper)
05/03/2009 Yogg-Saron 10 (2-Keeper)
05/24/2009 Yogg-Saron 10 (1-Keeper)
07/17/2009 Yogg-Saron 10 (0-Keeper)
07/20/2009 Algalon 10 [screenshot 1] [screenshot 2] [screenshot 3]
WoTLK Tier 8 (Heroic) Kills & Achievements ---
04/20/2009 Emalon 25 [screenshot]
06/03/2009 Flame Leviathan 25 (4-Tower)
04/14/2009 Razorscale 25 [movie]
04/20/2009 Ignis 25 [screenshot] [movie]
04/15/2009 XT-002 Deconstructor 25 [screenshot]
05/26/2009 XT-002 Deconstructor 25 (Heart-Broken)
04/15/2009 Assembly of Iron 25 [screenshot]
05/25/2009 Assembly of Iron 25 (Steelbreaker Last)
04/16/2009 Kologarn 25 [screenshot] [movie]
04/16/2009 Auriaya 25 [screenshot] [movie]
04/16/2009 Freya 25 (0-Elder) [screenshot]
04/24/2009 Freya 25 (1-Elder)
06/02/2009 Freya 25 (2-Elder)
07/03/2009 Freya 25 (3-Elder) [screenshot 1] [screenshot 2]
04/16/2009 Hodir 25 [screenshot]
05/12/2009 Hodir 25 (3-Minute) [movie]
04/18/2009 Thorim 25
05/14/2009 Thorim 25 (Sif Present) [movie 1] [movie 2]
04/19/2009 Mimiron 25 [screenshot]
07/07/2009 Mimiron 25 (Self-Destruct Button) [screenshot]
04/19/2009 General Vezax 25 [screenshot]
06/22/2009 General Vezax 25 (No Saronite) [screenshot 1] [screenshot 2] [movie]
04/20/2009 Yogg-Saron 25 (4-Keeper) [screenshot 1] [screenshot 2]
04/27/2009 Yogg-Saron 25 (3-Keeper) [screenshot 1] [screenshot]
06/22/2009 Yogg-Saron 25 (2-Keeper)
07/12/2009 Yogg-Saron 25 (1-Keeper) [screenshot 1] [screenshot 2]
09/14/2009 Yogg-Saron 25 (0-Keeper) [screenshot 1] [screenshot 2]
08/25/2009 Algalon 25 [screenshot 1] [screenshot 2]
WoTLK Tier 9 Kills & Achievements (Heroic) ---
09/02/2009 Call of the Grand Crusade 10
10/18/2009 Call of the Grand Crusade 25 [screenshot 1]
09/02/2009 Tribute to Skill 10
10/20/2009 Tribute to Skill 25
09/10/2009 Tribute to Mad Skill 10
10/20/2009 Tribute to Mad Skill 25
09/17/2009 Tribute to Insanity 10
12/01/2009 Tribute to Insanity 25 [screenshot 1] [screenshot 2]
06/10/2010 Tribute to Immortality 25
11/08/2009 Tribute to Dedicated Insanity 10
WoTLK Tier 10 Kills & Achievements (Heroic) ---
02/18/2010 Lord Marrowgar 10
02/16/2010 Lord Marrowgar 25
02/18/2010 Lady Deathwhisper 10
02/26/2010 Lady Deathwhisper 25
02/18/2010 Gunship Battle 10
02/18/2010 Gunship Battle 25
02/18/2010 Deathbringer Saurfang 10
03/01/2010 Deathbringer Saurfang 25
02/21/2010 Festergut 10
02/21/2010 Festergut 25
02/21/2010 Rotface 10
02/18/2010 Rotface 25
03/24/2010 Professor Putricide 10
03/30/2010 Professor Putricide 25 [screenshot 1]
02/21/2010 Blood Prince Council 10
02/19/2010 Blood Prince Council 25
02/21/2010 Blood-Queen Lana'thel 10
02/21/2010 Blood-Queen Lana'thel 25 [screenshot 1]
02/23/2010 Valithria Dreamwalker 10
02/18/2010 Valithria Dreamwalker 25
03/19/2010 Sindragosa 10
03/16/2010 Sindragosa 25 [screenshot 1] [screenshot 2]
05/23/2010 The Lich King 10
06/24/2010 The Lich King 25 [screenshot 1]
Cataclysm Tier 11 Kills & Achievements ---
12/20/2010 Normal Bastion of Twilight - [screenshot]
01/02/2011 Normal Blackwing Descent - [screenshot]
01/04/2011 Heroic: Halfus Wyrmbreaker
01/16/2011 Heroic: Chimaeron
01/19/2011 Heroic: Maloriak
01/24/2011 Heroic: Conclave of Wind
02/02/2011 Heroic: Omnotron Defense System
02/03/2011 Heroic: Magmaw
02/17/2011 Heroic: Atremedes - [screenshot]
02/28/2011 Heroic: Valiona and Theralion - [screenshot]
03/14/2011 Heroic: Nefarian - [screenshot]
03/31/2011 Heroic: Ascendant Council - [screenshot]
04/13/2011 Heroic: Cho'gall - [screenshot]
05/05/2011 Sinestra - [screenshot]
05/21/2011 Heroic: Al'akir - [screenshot]
Cataclysm Tier 12 Kills & Achievements ---
06/30/2011 Normal Firelands - [screenshot]
07/06/2011 Heroic: Shannox - [screenshot]
07/13/2011 Heroic: Lord Rhyolith - [screenshot][movie]
07/14/2011 Heroic: Beth'tilac - [screenshot][movie]
07/21/2011 Heroic: Alysrazor - [screenshot][movie]
07/28/2011 Heroic: Baleroc - [screenshot][movie]
08/01/2011 Heroic: Majordomo Fandral Staghelm - [screenshot][movie]