There is no current link that I’m aware of that lists all the included Startup and Lightbox content. It has the ability to generate a number of parametric primitives like cubes, speheres, cones, capsules, Torus, spirals, etc. It also comes with a huge number of brushes and alphas by default, and more via that Lightbox system. It has a decent selection of included models, like a few different male figures, at least one female figure, some heads, a dog I think. R7 comes with a few mechanically oriented models like a weapon and a mech walker. It has a quite a few Insert Multi Mesh brushes that are each made of of dozens of tiny machine parts.
In short, I think it comes with a generous helping of premade content by any standard, although it depends on what you’re comparing it to. ZBrush is a content creation engine, not a catalog of premade content. Any decision to purchase Zbrush should probably be made based on what you can create with it, not what comes already created.