BFBTester is good for doing quick, proactive security checks of binary programs. BFBTester will perform checks of single and multiple argument command line overflows and environment variable overflows. It can also watch for tempfile creation activity to alert the user of any programs using unsafe tempfile names.
XFMail is an X11 application for receiving electronic mail. It implements most of its email functionality internally so that it does not depend on a lot of extra packages. It supports POP3, MBOX, IMAP4, sendmail, and SMTP. It has built-in support for interfacing with PGP, GPG, ispell/aspell, faces, LDAP, and esound. It runs on most Unix variants.