Not much for the 13th Doctor yet in terms of novels (and no audios yet), but I'm sure the list will grow:
BBC New Series Adventures (Novels) The Good Doctor The Molten Heart Combat Magicks
BBC/Puffin Children’s Books (Novels) The Secret in Vault 13 The Maze of Death Team TARDIS Diaries 1: Paper Moon Team TARDIS Diaries 2: Ghost Town The Wonderful Doctor of Oz
Other BBC Novels At Childhood's End
Other Books The Runaway TARDIS
OPTIONAL: COMICS, SHORT STORIES, MISC. Short stories, e.g.: - The Missy Chronicles (The Liar, the Glitch and the Warzone) - Twelve Angels Weeping (The Rhino of Twenty-Three Strand Street) - Thirteen Doctors, Thirteen Stories (Time Lapse) - The Target Storybook (Gatecrashers) - Star Tales (That's All Right Mama, Einstein and the Doctor, Who-Dini?, The Pythagoras Problem, Mission of the KaaDak) Comic strips: DWM and Titan Comics are both producing 13th Doctor strips, so I'm sure we'll be able to utilise a lot of concepts. In fact, the latest issue from Titan Comics (The Thirteenth Doctor #9) features a character many people have been hoping we'll be able to include in the sourcebooks:
he latest issue of the Titan series gave us the first appearance of the Corsair.
The above information is a major spoiler as this is not revealed until the final panel of the issue. It was already included in spoiler tags in the OP, so I have added them to your post. I imagine that it'll be fairly general knowledge after the next issue is released, but at the moment it's a spoiler.