Google Chrome comes with a few plugins inbuilt/bundled. Here is a quick list of those plugins and a short description explaining what each of them do (and a link to a detailed article).

1. Widevine Content Decryption Module: This allows Chrome to play DRM-protected HTML5 video and audio. (like Netflix.)
2. Native Client: This allows developers to run C or C++ code on a web site. For the most part, this is really only used for some of the more complicated apps and games in the Chrome Web Store.
3. Adobe Flash: This is Adobe Flash, but tweaked a bit for Google Chrome.
4. Chrome Remote Desktop Viewer: This is the Chrome Remote Desktop app needed to access your computer remotely. The plug-in doesn’t do anything unless you activate it.
5. Chrome PDF Viewer: This one’s pretty self-explanatory: it’s the plug-in that lets you read PDF files.

Source: How-to Geek via Lifehacker.