The Keyboard Shortcuts Assistant provides you with a convenient view on the standard settings of your applications' keyboard shortcuts. You just press Ctrl+~ when your application is active.
It already contains an extensive list of keyboard shortcuts for the most popular applications. If the description of shortcuts for your specific applications is missing, try downloading a descriptions update from the Internet database, which is kept continuously updated. You may as well create a description of your own, and submit it to the database to share with others.