- Broken Movie
- "March Of The Pigs" original music video
- "Hurt" original music video
- "The Day The World Went Away" original music video
- "Every Day Is Exactly The Same" music video
- "Everything" music video
- The Fragile deluxe edition/5.1 surround
- With Teeth deluxe packaging/book
- The Social Network Dolby Atmos mix Ultra HD Blu-ray
- H-Gun Hate Tour film
- Simon Maxwell Further Down The Spiral Tour film
- Dissonance/Outside Tour film
- Lights In The Sky Tour film
- Tension 2013 Tour film
- Closure laserdisc and live album
- Closure DVD
- Gone Girl Soundtrack outtakes vinyl
- Patriots Day Soundtrack vinyl release
- Ghosts Film Festival
- Year Zero HBO show
- Doom 3 sound production
"Love Gun" cover
On the inside cover of the 1994 KISS tribute album, Kiss My Ass: Classic Kiss Regrooved, Nine Inch Nails is listed as one of the bands that did not participate in the album. Reporting at the time indicated that NIN was offered a slot for a cover of "Love Gun". Reznor had "all the best intentions to contribute," but he did not have enough time with the impending release of The Downward Spiral, and so there was no work done to even begin the cover. 
"Personal Jesus" cover
In 1998, it was reported by several news sources that Trent Reznor would be providing a cover of "Personal Jesus" for the Depeche Mode tribute album, For the Masses, produced by God Lives Underwater.   However, it did not appear on the final album. According to an interview with the album's executive producer, Nine Inch Nails really wanted to contribute, but were unable due to time constraints. 
String quartet recordings
After Reznor made an appearance at the Bridge School Benefit in 2006, a member of the string quartet hired for the performance stated that the songs had been recorded with Reznor in the studio.
Peter Christopherson Self Destuct Tour film
At the end of the interview contained on the bootleg titled Disturbed, Reznor mentions that Peter Christopherson is present for filming the show that night, to document that leg of the tour. The interview evidently took place in May of 1994, during the European dates of the Self Destruct Tour.
London 2005 footage
Both Brixton Academy shows of the With Teeth International Tour were filmed, but never released. Reznor stated in a post on nin.com/access that "we filmed and recorded the two Brixton shows. I'm not sure what we'll do with it yet, but I felt the band has solidified nicely and we're nearing the end of this phase of the tour."
Wave Goodbye Tour footage
The majority of the final club shows from this tour were filmed for some kind of release, though it was never stated if it would be a physical or online release. Videos of only two songs from those performances were uploaded to NIN's YouTube channel.  
Interscope greatest hits and remix albums
Just after NIN's release from Interscope Records in 2007, it was stated by Reznor that the label would be releasing a greatest hits album and a remix album, and that he hoped to be involved in putting them together. As this statement was made just days before Year Zero Remixed was released, the remix album would have been something different from that project. The hits album was referenced again when Hesitation Marks was released, because "Satellite" and "Everything" were originally written for it.
Zack de la Rocha solo album
After leaving Rage Against The Machine in 2000, Zack de la Rocha began working on a solo album with Reznor in which 20 tracks were produced. However, de la Rocha was unhappy with the album and the project was abandoned. Reznor has stated that a release of the album is unlikely anytime soon.
12 Rounds third album
A follow-up to 12 Rounds' My Big Hero had involvement from Reznor, but due to the collapse of Nothing Records, the album was never released. The band eventually obtained the rights to the songs and released a few of them online in 2009.
The Woman In The Window score
In 2018, it was announced that Reznor and Atticus Ross would be doing the score for The Woman In The Window. The score was completed and described as "avant-garde" by Reznor. . However, after some test screenings, the film changed direction with rewrites and reshoots, and Reznor and Ross withdrew from the film. The studio hired Danny Elfman to write a new score. Fans have sometimes speculated that the music may have become Ghosts V: Together/Ghosts VI: Locusts, but a quote from the film's director seems to indicate that the music was much heavier:
It was a lot more brutal in my original conception. Both aesthetically, with really fucking hard cuts and really violent music — Trent Reznor did an incredible score for it that was abrasive and hard-core — and in its depiction of Anna, Amy Adams’s character, who was far messier and kind of despicable in a lot of ways.