Look what I found!

The Doctor Tribute | 1963 - 2019 | Hartnell to Whittaker

"Doctor Who | The Doctor Tribute | 1963 - 2019 | Hartnell to Whittaker" (Watch on YouTube)

(There are even a couple of frames from the New Year's Special.)

ETA:

And then I came across an Extended Cut of 'The First Question'- 50th Anniversary Trailer

"Doctor Who: 'The First Question' - The Extended Cut - 50th Anniversary Trailer (HD)" (Watch on YouTube)