An Antilibrary consists of all the books that you have aquired but not read yet (or by extension those that you have bookmarked somewhere).
While the fact of having an ever-growing collection of books that you wanted to read but never get around to, I like the concept for that it takes out the pressure.
The concept of the antilibrary offers a shift of perspective towards future discoveries. The library is a sign of your curiosity which is valuable even if you haven’t read all the books yet.