A Cybercarrier was a class of Cyber-ship.
In the immediate aftermath of the Cyber-Wars, an abandoned Cybercarrier carrying hundreds of thousands of Cybermen warriors and a fleet of Cyber fighters was discovered by the Lone Cyberman and his Cyberguards through the Cyberium at the site of the Cybermen's greatest defeat. (TV: Ascension of the Cybermen) Travelling to the Planet of the Boundary, Ashad intended to rebuild the Cybermen as a purely robotic race before using the death particle to wipe out all life in the universe.
After receiving an invitation from the Master, Ashad brought the carrier to Gallifrey where the Master used the cyber conversion chambers to turn the corpses of the Time Lords into his own army of CyberMasters. The carrier and its army of Cybermen were later destroyed by the Thirteenth Doctor and her companions using explosives planted throughout the ship, including several near the core. However, due to the explosives activating early, they barely escaped the blast. (TV: The Timeless Children)