Dr. forever!
From Tardis Wiki, the free Doctor Who reference
Doctor Forever! was a five-part series of documentary featurettes that were included on several Doctor Who DVD releases.
Parts
The Celestial Toyroom, released on The Aztecs: Special Edition
Love and War, released on The Ark in Space: Special Edition
The Apocalypse Element, released on The Visitation: Special Edition
Lost in the Dark Dimension, released on Inferno: Special Edition
The Unquiet Dead, released on The Green Death: Special Edition