Dalek Khan saves the Daleks from destruction by the Hand of Omega
Maybe this happened - the New Paradigm Daleks came from somewhere, right? It was never explained how they came about, but of course we all wish that the New Paradigm Daleks had never been created in the first place. In any case, this series of videos explains how it happened that the New Paradigm Daleks enlisted Dalek Khan to go back in time, prevent the Hand of Omega from destroying Skaro (seen in a 7th Doctor story), and setting up the conditions for the New Paradigm Daleks to come into existence. All we were told was Khan flew into the Time War, and went mad by seeing all of time and space. Maybe we'll never see an explanation in televised Doctor Who, so this will have to do.
Deep dive into Shepperton and the making of Daleks Invasion of Earth 2160AD
The second Peter Cushing Doctor Who film, Daleks Invasion of Earth, was filmed at the Shepperton studio complex. The outdoor set at Shepperton used for street scenes had a weird amalgam of building styles, some from New York City, because that set had been used for so many different movies including a Warren Beatty movie set in New York. The massive entrance to the mining works was in fact a small hill on the backlot, with a matte painting filling in the background. The pseudo-medieval farm house was another building on the Shepperton site.
Nicholas Briggs - the Voice of the Daleks
In modern Doctor Who, Nicholas Briggs is the primary Voice of the Daleks. In every appearance of the Daleks of the modern era, Briggs provided the voiceovers, and yes that included the scene where Martha Jones went to a castle in Germany with the Osterhagen Key and the Daleks were shouting EXTERMINATE in German.
The Dalek Supreme and the Planet of the Daleks
A deep dive into the Daleks shown in The Planet of the Daleks shows a surprising source for the color schemes. Television Daleks have largely not used bright color schemes, other than those overweight Daleks that Matt Smith faced. But Terry Nation, when putting Daleks into non-Television formats, had used ones with bright color schemes.
The Mystery of Terry Nation's Special Daleks
Planet of the Daleks featured a previously unseen Dalek, Dalek Supreme, with a distinctive black and gold casing. That Dalek came from Terry Nations private collection of Dalek casings. By carefully looking at physical characteristics one can trace the history of these casings through pictures appearing in magazines and elsewhere. Many think Terry Nation's personal Daleks are movie props from "Daleks Invasion of Earth 2150 A.D." A careful study of the Daleks in that movie identifies specific characteristics corresponding to the Daleks in Terry Nations collection. Even more careful study says that some of the Daleks in the movie were built for a stage play, Curse of the Daleks.
The disaster while shooting The Chase on the beach at Camber
A part of The Chase was the first time Doctor Who was shot at a real location, the beach at Camber. There were special considerations for operating Daleks on a beach, which involved what was called a "Hover Dalek" that was light enough for the Dalek Operator to walk it around rather than roll it on wheels. That same Dalek was used in a later scene on the Marcy Celeste - it's the one which fell in the water - and in an even later scene at the house of horrors, when Frankenstein's Monster picked up a Dalek to smash it. This Dalek is known to have appeared in many other shows all the way to Remembrance of the Daleks. That Dalek's original purpose was to emerge from the sand, but they were unable to do so with a full size Dalek, and ended up building a smaller Dalek where they could film it emerging from some sand. The model was later used in The Daleks Master Plan.