Chrome native client, Flash plugin (built in), PDF browser.
The PDF browser is the only one useful to me, and it's been broken in Linux for the last 3 versions of Chrome...
Some of the newer WebKit features are getting bloated as well, and are built-in even if you don't need them - e.g. the new Javascript de-obsfucation feature in the developer tools.
Don't know about you but I prefer my plugins to be auto-updated to the latest, safest versions. Last I checked the non-bundled Flash still had to be manually updated from time to time by the user. The built in Flash/PDF is updated with Chrome. You might not think this is useful, but just wait till you click on a link and get pwned. Even if you don't, because you're on Linux, what about your parents?
That's a genuine question, the only thing I can think of is the 'Apps' dashboard with a link to the Chrome Web Store, apart from that Chrome seems to consist of just the essential elements of a browser.