Continuing with the discussion about Toy Story and obscure/exclusive content. There's a decent amount of Laserdisc exclusive content.
There's a lot of Disney that has been altered since it's release on Laserdisc. The Beauty and the Beast Work in Progress is the most significant. See the full comparison here:
http://stayornay.com/toons/index.php/2015/05/17/beauty-and-the-beast-work-in-progress-version/
Lion King also has a ridiculous amount of changes in addition to the infamous "SFX" scene.
https://lionking.fandom.com/wiki/The_Lion_King_series_re-release_changes
When a lot of the older Disney was "restored" for DVD/Blu-Ray, colors and details were lost. Cinderella suffered from this in very obvious ways:
https://www.boredpanda.com/disney-animated-movies-ciderella-blu-ray-restoration-ruined-detail/?utm_source=google&utm_medium=organic&utm_campaign=organic
There's always Song of the South which was only released on VHS and a Japanese Laserdisc pressing. That one tends to fetch fairly good money.
The Rescuers and Who Framed Roger Rabbit both have a scene where a naked woman is present for one frame. The animators slipped it in thinking it would be never noticed in the cinema (which it wasn't). It was only noticed on CAV laserdiscs with frame by frame playback capabilities. Both titles were recalled and re-released with the frames removed.
Up until last year with the release of Disney Plus, the only widescreen version of A Goofy Movie was on Laserdisc. Everything else was pan & scan.
There's also some banned Looney Tunes and Tex Avery cartoons only present on laserdisc.
Looking at George Lucas. The most famous instance is Star Wars. As others have mentioned, laserdisc is the highest quality official release of the original trilogy in it's theatrical form (with the exception of the GOUT DVD release which is sourced directly from the laserdisc with no cleanup work). It is also the highest quality official release of the 1997 Special Edition trilogy in it's theatrical form. The 2004 DVD releases use a completely different cut, as do the Blu-Ray. Episode 1 also has an exclusive laserdisc release in Japan. Japan got the theatrical version of Episode 1 on Laserdisc with puppet Yoda. Everyone else got an extended cut. When Episode 2 came out, puppet Yoda was removed in Episode 1 and replaced with a CGI version (which is what you get on all re-releases of Episode 1).
But, it's not limited to Lucas' Star Wars. American Graffiti and THX 1138 have been altered from their original theatrical releases with laserdisc being the only way to see the original theatrical cut. American Graffiti has minor changes, but THX 1138 has a ton of changes, and suffers from the same CGI crap that Star Wars does:
https://www.movie-censorship.com/report.php?ID=541751
The Matrix laserdisc release is different then the DVD release and is supposedly more true to the theatrical version. The DVD has a green tint throughout the entire picture. I've never seen the laserdisc to compare, so I can't say how different it actually is.
Scream has some laserdisc exclusive content. While it is only 20 seconds worth of additional content, it's somewhat significant.
https://www.lddb.com/laserdisc/07764/10499-AS/Scream:-Directors-Cut
There are some commentary tracks that are exclusive to laserdisc releases. The most famous are the banned commentary tracks for the 3 James Bond Criterion Collection releases. They were recalled and re-released without the commentaries. There are also a lot of commentaries by film historian Ronald Haver that are on Criterion laserdiscs but not always on the re-releases.
In general, laserdisc typically has a more "accurate" version when comparing to the theatrical release (not always true though- IE pan & scan). Soundmixes are typically the original theater mix and not a near-field mix that is present on DVD/BluRay. I've compared several titles over the years and almost always, the laserdisc blows anything else away soundwise.
One of the more well known laserdisc exclusive releases is Michael Mann's The Keep. There was a ton of drama with it's production, he hated the final product, and it has not ever been re-released.
There's a lot more, but this is what I can think of off the top of my head.