I have all three of the main books.
I have the Outposts graphic novel.
I have all three of the Metro games, their DLCs, and both of the Redux editions.
I thought I had it all...
But recently I have found out that there are like 40 something expanded universe books that I cannot read because none of them are in English and my foreign language skills are crap...
Welp... time to approach Dimitry and ask for a translation service overhaul... or approach Google in making smart glasses that translate what you are reading from one language to the next...