In Metro 2033 (the book by Dmitry Glukhovsky although in the game as well) the main protagonist encounters "librarians" in the Russian State Library. Those are described as "Gorilla"-shaped mutants.
In the Unseen University, the Librarian is a wizard transformed into an orangutan.
Are the librarians of Metro 2033 homage to Terry Pratchett or is it just coincidence?
Almost certainly it's an homage. The author of the Metro 2033 book was an avid collector of a particular Russian fantasy novel book-club series when he was younger and mentions that these translated books contained some Terry Pratchett novels.
Someone who enjoys the Discworld books could not have failed to make the mental connection between a large ape-like creature that exclusively dwells in the library area and the Librarian from Unseen University.
On the other hand, there was this fantasy series… all the books were in the same design and they had numbers on the side and you were supposed to collect them. The books were not interrelated at all… there was, like, Anne McCaffrey, Michael Moorcock, Terry Pratchett… everything put in the same series. And I was just a fan of collecting these books. As soon as they came out I just ran to bookshop to get the new one, just so I could put it on my shelf.
