PB&J Otter (lost original credits sequences of Disney animated series; 1998-2000)
Although the entire PB&J Otter series has resurfaced after Disney Junior rebroadcast it in the USA from 2012-2013, many of the episodes' original credits instrumentals remain at large. Originally PB&J Otter credits sequences featured instrumentals of the songs featured in the episodes (or in rare cases, background music) but due to Disney Junior shrinking and muting the credits in reruns, several of these are missing. Thus far, only Season 3's credits instrumentals have surfaced online as off-air recordings from Playhouse Disney Asia (albeit, some with 1-2 seconds cut off) along with select instrumentals from the other two sequences from various off-air recordings. A few of these come from off-air Greek recordings, although these recordings cut off before the closing logos are shown, rendering these incomplete and the full versions lost.
The likelihood of these showing up on YouTube is low due to OtterFan25 (who had previously uploaded many of the show's credits instrumentals), getting two copyright strikes from Dan Saywer for his videos, meaning anybody who uploads these is at risk. However, a few videos from wrightgirl11 remain along with other users' uploads of episodes with credits at the end.
Credits instrumentals remain at large for 19 episodes and at least 6 of the found instrumentals cut off early.
Update 1/9/14: Disney Junior has put one of the missing credits instrumentals on demand for the episode "Gotta Dance / Otter Pox" and we can expect a MEGA mirror in the next few days!
Update 6/16/14: The credits for "A Tree Grows in Hoohaw / Flick's Big Fakeout" are available on Retro Junk!