At 40 seconds, this is right on the edge of what I would consider recognising as a Doctor Who mini-episode.
Donna: "There are things waiting in the darkness. Creatures of metal, fire and blood. But he's out there, burning through time, facing a thousand dangers across the stars, and never giving up. He looks like a man, but he's a legend. And his name is the Doctor. He'll come back to save us, and this time, I'm gonna be ready. Then - just like that - p' - we'll be gone."
Produced to publicise the 2008 series, it features Donna Noble sitting at a camp-fire talking about the Doctor in the same dreamy manner as all female companions do these days. (Tegan would kill her) It's interspersed with shots of Daleks, Sontarans and the odd Ood, although she does not refer to them by name. Although they were intended as flash-forwards for the audience of the day - who hadn't seen season 30 yet - they appear to be flashbacks for Donna.
The snag with that is placing when this campfire monologue happens. In the series, Donna does indeed meet all three featured races, but upon encountering the last of these, promptly loses her memory of them all, and the Doctor. Given that she is waiting for him to return to save her and whomever she's speaking to, just when can this scene take place?
I'd put it in-between the two episodes of Silence In The Library and Forest Of The Dead. Donna had met both the Sontarans and the Ood by this point, and had probably found out about the Daleks during her investigations into him prior to Partners In Crime. Additionally, at this point in history Donna is suffering from intermittent amnesia of her travels with the Doctor anyway, as she is being integrated into an alternative existence in an artificial reality. In Forest Of The Dead her medical doctor - Doctor Moon - then treats her to forget her flashes of memory from that past life.
There are also three much shorter edits featuring each monster with no dialogue, but they are just cutdowns of this full-length trail.
And then - just like that - p' - it was gone.