Made for DVD minimovie gap fillers, typing up things from a movie to its sequel. The only ones I can think of are "Rings" included on the Ring 2 unrated disc, as well as a standalone bundled with part 1. And then there's the (i forget what it's called) little movie that connects Fast and the Furious with 2Fast. It's on the 2Fast DVD and the Tricked Out version of part 1.

Maybe Shrek 3D counts too?

Shrek 3D wasn't made for DVD, it was made for an amusement park ride, and then later released on DVD.

24 has had some of these type of short films that link the events from the previous season to the new season.

I know Shrek was originally Shrek 4D at Universal Studios, but I think it's supposed to go between the two movies. And I forgot about 24.

Wasn't there a riddick anime as well? Could that be considered a mini?

XXX 2: State of the Union had a thingy explaining what happend to Vin Diesel's character.

Rings was a helluva lot better than Ring 2.

Animatrix -> Matrix

Well, it's not actually a minimovie, but along the same lines was the Star Wars: Clone Wars animated series that took place between Attack of the Clones and Revenge of the Sith

The problems with Animatrix, Clone Wars, and Riddick is that they weren't included on the DVD of the original or sequel, they were separate DVD releases.

It wasnt included in a DVD and not exactly a bridge between movies , but I remember Van Helsing: The London Assignment was a cartoon prequel to the movie.

I believe there was one for 2 Fast 2 Furious to bridge the gap between it and the first movie.

Maybe not what you're thinking of, but 24 season 4 has a bridge to season 5.

Why yes it was.

And these are all good guys, although 24 and 2 Fast 2 Furious were already mentioned in the first two posts.