Certain digital rewards are being bundled by Valve and will be available as another Steam key on BackerKit. We will let you know when those are available!
We've been receiving reports of backers having problems downloading the DLC for Companion Creatures and have been working with Valve to figure out how to properly distribute these rewards since this could affect the distribution of our other digital rewards.
You can see the list of digital rewards' status here:
Rewards listed for "Launch" will be available as soon as we figure out the distribution issue with the Companion Creatures.
Rewards listed as "Post-Launch" will be tracked in a longer KS rewards update post either this week or the next.