You can use the build in fields for that. On our site we use clubs for featured games, so I simply put the link to the club in a field, looks like this https://prnt.sc/vfh4xi
Of course you can use topics too and place the field in the sidebar or below the main content of the game.
@Adriano Faria your Books application seems to have a cool feature called Bookshelf. How about some kind of button a user can click and add a game to his collection? Must not be such powerfull like the Bookshelfs, maybe just a profile tab with the games they own?