You can also have a .forward file, which is not strictly speaking an ``init file''. If it contains an email address, then all mail to you will be forwarded to that address instead. This is useful when you have accounts on many different systems, but only want to read mail at one location.
There is a host of other possible initialization files. The exact number will vary from system to system, and is dependent on the software installed on that system. One way to learn more is to look at files in your home directory whose names begin with ``.''. These files are not all guaranteed to be init files, but it's a good bet that most of them are.