You can imagine pi for one trivial example. It has infinite details but it's not infinitely interesting. You can map it to infinite boring story (let's say John moves west/east depending on the next binary digit :) ).
Kolmogorov complexity is the formalism around that distinction.
EDIT now that I think about it - if you take PI in binary and interprete it as utf-8 - every single book every written (or that will ever be written) is in there somewhere :) And there are algorithm to calculate PI to arbitrary digit that are pretty simple.
> take PI in binary and interprete it as utf-8 - every single book every written (or that will ever be written) is in there somewhere
It isn’t proven that pi is normal. Also, even if you were to find a book in the sequence of pi, the index of where it starts would (generally) be vastly larger than the book itself.
Imagination is the tool, not the storage space. The tool has boundless potential to create things in your mind. In other words, the tool is boundless or "infinite" in its ability. Given a mind that lasts forever there's no reason to believe there's a cap on what is possible for a mind to imagine and there are biological creatures that are immortal (e.g. hammerhead worms) so there's at least some reason to believe our minds could one day become immortal (at least in the sense of immune to decay).
I certainly don't have ideas for infinite stories in my mind. And I don't read a book to discover a good idea that I already had.