1. v4.master - This is default master page.
2. default.master - this is used to support the 2007 user interface
3. minimal.master
4. simple.master- it is used for accessdenied.aspx, confirmation.aspx, error.aspx, login.aspx, reqacc.aspx, signout.aspx & webdeleted.aspx pages.
There are two more master pages for application pages as below:
application.master
applicationv4.master
both of above reside at 14 hive folder and used for the application pages.
