This is my dedicated NIN page where I will be discussing the entire discography, specifically their main releases as I do not care about the other stuff;

So here's some more links to dedicated pages for them:

• Pretty Hate Machine (1989)
• Broken (1992) UNAVAILABLE
• The Downward Spiral (1994) UNAVAILABLE
• The Fragile (1999) UNAVAILABLE
• With Teeth (2005)
• Year Zero (2007)
• Ghosts I-IV (2008) UNAVAILABLE
• The Slip (2008)  UNAVAILABLE
• Hesitation Marks (2013) 
• Not the actual events (2016) UNAVAILABLE
• Add violence (2017) UNAVAILABLE
• Bad witch (2018)
• Ghosts V-VI  (2020)  UNAVAILABLE

             also here's a link to their official website