(I'm using a template from my November post, because it explains what I'm doing.)
Sometimes Audible rewards attentive members with not only the choice of two free audiobooks every member gets, but also a brief chance to preorder several of the same audiobooks that will be part of next month's choose-two offer. If you preorder these (for free), you'll own them when the choose-two deal goes live, and you can choose from the others without losing these.
Let's keep this up to date and see how many we get.
... and apparently just added on the 19th, here's a bunch more free preorders with the same release date: