I really love Wolfe for his small almost throwaway visions of the future, which are used like an aside in a few lines and mostly inconsequential to the story.

In the Urth of the New Sun for example he has a kind of AI lock, the only function of which is to recognize a person and open only to that person. Being in that role for thousands of years, some of the locks develop a kind of personality or at least personal traits, but they are totally defined by and cannot exceed the role they were initially given, nor do they want to. It is still a haunting image for me how personality or something close to a soul might be an accidental byproduct of something as mundane as wanting to have a convenient lock. And of course you cannot stop to wonder how far we are from that.

In Book of the new sun there is the Green Man who Severian saves from imprisonment. He only appears on a few pages but we learn that he is from a distant time where mankind incorporated plant cells in their genetic makeup in order to perform photosynthesis. That brilliantly plays on two themes of the book: the sun as live giving and how a single person can be independent (or "autarch"), here in so far as producing their own energy.

There are many more instances and it’s what makes the Book of the New Sun or the Solar Cycle so fantastic. The future is so vast and strange here, that it cannot be fully depicted and ideas which another writer would stake a whole book or series on are only good for a few lines.