Omega Arsenal

The Omega Arsenal was a collection of forbidden weapons locked in the Time Vaults on Gallifrey. During the Last Great Time War, the Time Lords used all the weapons in the Arsenal against the Daleks except for one: the Moment. This was stolen by the War Doctor in the final day of the War. (TV: The Day of the Doctor)

Behind the scenes
The "Fourth Dimension" feature on the BBC's Doctor Who website suggests that the Omega Arsenal is a reference to Omega.