1. "The Wheel in Space"
Honestly, I'm quite surprised that this story hasn't been animated in full already. While it's not a perfect story, it is a Second Doctor serial featuring the Cybermen, which would make it an easy story to sell. On top of that, it introduces Zoe to the TARDIS crew, making "The Wheel in Space" quite significant.
The oddest thing is that the story has been partially animated already. In 2018, a condensed version of episode 1 was animated for the 25th anniversary of Missing, Believed Wiped, an annual event hosted by the British Film Institute designed to raise awareness of missing episodes from British television. This animation was later included as a special feature on "The Macra Terror" DVD in 2019.
Since then however, there has been no update on animating "The Wheel in Space" in full. No hint if it would continue in exactly the same style, or even start completely from scratch. In fact, since the small preview was released, all the missing episodes have been animated in 3D by Iz and Steve Skinner. We'll be taking a deeper look at these animations soon, but I have to admit: the work is impressive, and it's a shame that it's not getting an official release.
Still, despite all of this, I can't help but think that "The Wheel in Space" is still high on the BBC's agenda to release, even if they'd prefer to work on their own separate animation. Once animated, it'll make it even easier to release Season 5 as part of The Collection on Blu-ray, as well as bring an important part of Doctor Who's history to a larger audience.