I wanted to log all the missing tid-bits of audio / sound effects I found so far, and I know you care enough about the films so it’s worth compiling and giving you the info. I honestly don’t imagine there is much more than this list but it’s perhaps worth compiling a list as there is not one as far as I can tell.

Captain Atillies thrown against the wall - Proper sound of hitting the Tank cynlinder not on set Audio found in German Dub and Radio Drama
Landspeeder Search for R2-D2 - Radio Drama has Blip sound effect for scanner
Sand People Attack - Radio Drama has Antony Daniels Shouting as he falls from the cliff and Hit sound for The Sand person Thrusting his Staff in to Luke, Luke also responds with a yelp
Krayt Dragon Call - The Radio Drama features the Original Krayt Dragon call which comes in a bit earlier in this version you can also hear the sound of the Land Speeder Parts falling on the ground as the Sand people Turn in Surprise
Alderaan Destruction - Mottis footsteps were used for the previous scene featuring the death star view screen (part of this sequence is put into the Battle of Yavin Sequence) Music Cue incorrect and Death Star firing Sequence missing sound for some of The Gunner Operators pulling Levers and “Stand By” voice over announcement absent.
The Death Star Core - When Leia Shoots the Storm Trooper that slumps on the ground the Audio for falling on the floor is found in the Original Theatrical Trailer.
Vader & Kenobi Duel - Just Before Obiwan Get’s the Chop the sound of the 2 Lightsabers Briefly Kissing is Absent although Flashes are Present. There is a bit in the middle like this also sound missing for the kisses.
On the shot of the Falcon escaping the Deathstar flying towards camera the Death Star in the Background The music cut’s off Abruptly. A shot was pinched from this part and used for the Falcon Flying away from the Death Star Trench that was in the Theatrical Version replaced in the Special Edition. I am still yet to try it but I am pretty shure it’s a missing 2 seconds music and booster sound but I saw a version of the precceding shot with some omninous green flashes around the death star in a documentary so there could be a bit more to the sequence but not all that much. i.e it’s possible it was planned that the Death Star turrets around the Hanger let a couple of shots off before the Falcon got intercepted by the Tie Fighters.
When the x-wing has the Hatched closed before Luke Takes off with Voice over from Ben Kenobi. The sound of the Hatch Closing and being sealed can be heard in the Radio Drama.
Falcon Landing in Death star Hanger (tractor beam) - Siren from trailer was possibly planned at some point as the troops congregate around the ship.

There could be a few more, this is the current list and discovery compiled but this is I hope a helpful list of Alternate and Missing Audio either way.