Extinct chapters
This page is dedicated in remembrance of all those Space Marine Chapters that are entirely and definitely very dead. This does not include chapters that fell to Chaos, so all those lost (wiped out, turned heretic, barely survived or still missing) during the Abyssal Crusade aren't listed here, for that see Judged. Special mentions to the 2 lost legions.
Angels of Retribution
One of those Chapters made to fill in a spot, they were destroyed entirely in an ambush on the planet Alantor X. Allegedly, the Officio Assassinorum was involved.
Astral Knights
Sacrificed their chapter to destroy the Necrons' World Engine in 926.M41. Last few survivors, consisting of 30 Marines and Dreadnought Thade (who was effectively Chapter Master), either attacked their replacement Chapter (the Sable Swords) and wiped out or convinced by the Sable Swords to partake in a Crusade until their deaths in battle. Regardless of the actual fate, all survivors were killed as well.
Crimson Castellans
This chapter was fighting against renegades from their own chapter when a Tyranid Hive Fleet came by and ate them both.
Crimson Consuls
Seriously, don't put crimson in the chapter's title if you want it to live. This chapter was taken out piece by piece in a series of freak accidents which were only discovered to have been arranged by the Alpha Legion when their battle-brothers' subliminal programming was activated to wipe out the Chapter leadership.
Dark Paladins
Annihilated by Necrons while investigating Jarrman Prime.
Emperor's Swords
Destroyed by the Alpha Legion who contaminated their recruiting pool and implanted subconscious triggers in their recruits.
Emperor's Swords again
Based on Bellicas, which turned out to be a tomb world. Begin face-palming.
Fire Hawks
Lost in the warp. Surviving members may or may not make up the Legion of the Damned.
Fists Exemplar
Discreetly replaced the completely depleted Imperial Fists along with a handful of other volunteers from the Imperial Fists' other successors after The War of The Beast, with their records purged on orders of their last Chapter Master Maximus Thane (he became the rebuilt Imperial Fists Chapter Master) after it was discovered that the remaining members of the chapter had defected to the Iron Warriors (specifically, a unit under the First Captain was forced to ally with them during WAAAGH! The Beast as they lost contact with the Imperium, but one company managed to return and also joined the rebuilt Imperial Fists).
Flame Falcons
Declared excommunicate traitoris by the Inquisition and officially extinguished by Grey Knights. Few survived.
Imperial Fists
Destroyed in War of The Beast, secretly replenished with Fists Exemplar and other successors thanks to the Last Wall protocol.
Knights of Blood
Sacrificed to a man in a desperate effort to protect Baal from the Tyranid and Khorne-Daemon smackdown. Due to their reputation as borderline-heretics, it wasn't rebuilt in the Ultima Founding.
Knights of Eternity
Another chapter presumed to have been eaten by the Kraken.
Obsidian Glaives
Chapter destroyed by the Red Waagh. Detailed in Sanctus Reach campaign.
Sable Swords
Extinct by M41. Refounded to replace Astral Knights.
Soul Drinkers
Declared extinct. After becoming disillusioned with the Imperium and turning renegade, they were finally brought to trial and ended up sacrificing themselves to fend off a daemon army, the three loyalist survivors exiled themselves to the warp along with their Chaos turned brother. Have apparently been recreated with Primaris Marines as part of the Ultima Founding.
Tiger Claws
Lost in the warp, surviving members absorbed by their founders, the Astral Claws, who later caused the Badab War and turned traitor as the Red Corsairs after escaping following the defeat.
Unnumbered Sons
The initial reserve of Primaris Marines before they were entirely reorganised into existing chapters or formed new or legacy chapters. Not technically extinct, but no longer exists as a functioning unit.
Wolf Brothers
Succumbed to the instabilities of their gene-seeds. Any survivors are now feral wulfen or renegades fighting among the Red Corsairs and possibly Skyrar's Dark Wolves.