The Hidden Wiki was the first and original tor hidden service link list / collection in a wikipedia style wiki format.
The original site running the Hidden Wiki is long gone, but there are many new Hidden Wiki sites that have been created since then.
(you need Tor Browser or Tails etc to browse those sites, or add .lt to the domain, example: http://wikitjerrta4qgz4.onion.lt/ )
So what can you find on the hidden wiki?
There are many reasons people go to the hidden wiki, some for political reasons, some for the large marketplace of drugs and guns and things like fake ids, fake passports and stolen creditcard or counterfait cash. Just stay away from the so called “Hard Candy” sites, Hard Candy is basically just another word for Child Porn.