Elliott Kay has a Patreon, and regularly posts stuff there. It includes short stories, sneak peeks for upcoming works, world building notes, and AMAs.

Some similar wikis include Patreon material indiscriminately (eg October Daye), but I'm not sure it's the best route. On the other hand, that stuff is posted there is of interest in and of itself.

I'm thinking of not using any of the information posted on Patreon, but include the short stories in the bibliography and series overview pages. That information is publically available, though the content itself is locked.