Sailor Moon (partially found unreleased full soundtrack of DiC English dub of anime; mid-1990s)
Cover art for the Sailor Moon CD that was found by the composer of the DiC background music soundtrack which contains some of the cues.
Status: Partially Found
During the mid-1990s, two companies, DiC and Toon Makers, were battling for the rights of the anime Bishoujo Senshi Sailor Moon. DiC wanted to localize it for North American syndication, while Toon Makers wanted to rework the anime series entirely, into their live-action/animation Americanized version. In the end, DiC received the rights to the first two seasons of the series.
DiC had altered several things during their tenure with Sailor Moon, such as choosing to replace the already made Japanese soundtrack with their own, in-house work. DiC hired two separate music companies to work on the vocal and background music respectively, music producer Michael Benghiat and his music company "The Music Kitchen" worked on the vocal soundtrack  while music composer Bob Summers and music producer Don Perry and his music company "Don Perry Music" worked on the background music soundtrack.  Even though the vocal music, including the insert songs and theme song got three official CD releases, the background music soundtrack have never been released in their entirety.
On November 12th, 2002 only nine cues from the DiC background soundtrack were released on the "Sailor Moon: The Full Moon Collection" CD. 
From 1998 through 2006, a fandubber by the name of Andrew Dowler operated his own Sailor Moon fandub group called Negavision. It wasn't until 2001,when Andrew was somehow able to get a hold of some of the cues from an outside third party and used them in his Sailor Stars fandub.  Regardless, Andrew Dowler at the time had no intentions on releasing the cues he had. Negavision would eventually stop all activities in 2006 and Andrew Dowler has ever since moved on with life.
Going as far back as 2013, many fans of the DiC soundtrack have made many attempts to get the soundtrack released including creating petitions to raise awareness and gain attention from record companies who may show interest in releasing the DiC soundtrack but to no avail.  Some fans, even going as far as to rip and piece together some of the music themselves.
In February 2021, a Youtuber by the name of TF1945, contacted the composers of the DiC background music soundtrack Bob Summers and Don Perry to ask them whether they had a copy of the soundtrack, which they did not. However, in September 2021, the composers did find a CD that was made during the early production of the DiC dub that contained some of the cues including demos and unused tracks to which TF1945 uploaded on one of their YouTube channels named "Project Sailor Scout" on September 11th, 2021, which they also made available to download.
In July 2022, TF1945 contacted Andrew Dowler about the DiC Cues and didn't receive a response until December. Andrew later responded and sent his collection over for archival. His collection was made listenable via YouTube on December 11th, 2022; with download links provided and a txt list of names. 
Unfortunately, the entire DiC soundtrack is still lost with only 88 tracks out of an estimated total of 191 cues having been found.
The DiC background music soundtrack is currently owned by a Canadian company Wildbrain who acquired DiC Entertainment's properties. 
- Pretty Guardian Sailor Moon: The Miracle 4-D (partially found short film based on anime series; 2018)
- Sailor Moon (found Toon Makers' live-action/animated pitch pilot of superheroine anime based on manga; 1994)
- Don Perry Music official website.
- Wildbrain official website.
- Forum page discussing Andrew Dowler and the DiC cues he used for his fandub.
- Archived page of Andrew Dowler's fandub Negavision.
- A list of the estimated total of DiC cues compiled by Corza Moon.