The Anachronauts were an army amassed from different periods of history and alternate realities and trained by the Eternal warrior Gilgamesh to be Kang's elite army and guards.
The Anachronauts were created by Mark Gruenwald and Dan Panosian and first appeared in Fantastic Four Annual #25.
The team were introduced in the Citizen Kang crossover storyline, and despite Marvel's attempts to push them as a property, they failed to garner enough interest. They reappeared in Citizen Kang's sequel The Terminatrix Objective and returned, with a different roster, in The Crossing.
The Anachronauts were later slain by Immortus who was invading Chronopolis to obtain the Forever Crystal. Wildrun was the only survivor of the slaughter and he eventually perished too when Immortus destroyed all of Chronopolis.
More recently, a divergent Nathaniel Richards assembled his own team of Anachronauts to battle members of the Fantastic Four, Doctor Doom and another version of himself. No further context was given and none of the Anachronauts were given names, let alone character.