Doctor Who: Every Version Of The Doctor Explained
3. The Timeless Children (First Appearance: 2020)
It's arguable that all seven Timeless Children don't count as versions of the Doctor, as they hadn't yet assumed the title. However, they do represent the Doctor as a child.
The Timeless Child was how the Doctor was originally known when she was discovered by Tecteun.
A being of unknown origin, the Timeless Child had the ability to regenerate infinitely, and was experimented upon by Tecteun, who ultimately unlocked the secret of regeneration and spliced that DNA into certain Gallifreyans, who renamed themselves Time Lords.
Tecteun's experiments resulted in at least seven separate incarnations of the Doctor. It's unclear how long each of these children lasted, but what is clear is that Tecteun isn't winning any mother of the year prizes any time soon.