Mysterious games/challenges/scavenger hunts or Alternate Reality Games

I’m looking for books, preferably with an audiobook version, that are about mysterious games that the protagonist must solve for whatever reason.

If you’ve heard of Rabbits by Terry Miles, I’m looking for something like that. Or a better version of Ready Player One.

Games or challenges or scavenger hunts where the protagonist has to look through old books, darknet message boards for strange hints or something like that.

If there are SciFi or Fantasy elements, that’s cool too.

Thanks!

by Party-Permission