One incarnation of this unit has been completely destroyed, used by mimetic aliens to infiltrate Earth. The originals were likely discarded.
A Matter of Time - Daniel Jackson joins SG-6 in a dig expedition to P3X-118.
In the Line of Duty - SG-6 assists SG-1 as they pull Nassyan refugees from their world during a Goa'uld bombardment.
Into the Fire - SG-6 assists in the rescue of SG-1, captured by Hathor.
Foothold - Mimetic aliens capture SG-6 and use their forms and memories to infiltrate Earth. After the incident, their access codes are locked out, preventing them from ever returning.
Scorched Earth - SG-6 is assigned to seek out an alternative homeworld for the Enkarans.
Red Sky - Two members of SG-6 are killed in a launch pad explosion on K'Tau when several local radicals believe it is the will of the gods (the Asgard) that their people be destroyed.
Icon - SG-6 travels to Tegalus to help pull Dr. Jackson from the planet, which is immersed in a civil war.
The Fourth Horseman, Part 1 - SG-6's encounter with a Prior allows the powerful being to relay a plague to Earth.