|Someone else's collection, not mine...|
As for extras, Shatner and Nimoy's commentary on 4 is worth the listen (by Shatner's own admission, theirs was a relationship that frequently waxed and waned, but at this point they were apparently friendly with each other and happy to spend the time together). But Nicholas Meyer's director commentary on The Wrath of Khan is stellar. He is critical of his own errors in judgment, as well as indulgences he allowed some of the principal actors. He beautifully articulates the high-wire act every director has to walk when dealing with the studio, the franchise, and even a star like Shatner.
That any of these films made it to the screen is nearly miraculous -- that a few of them managed to be entertaining, beyond miraculous.