Contents of perl5 MailTools class:

Mail::Address - Parse mail addresses
Mail::Alias - maniulate mail alias files of various formats
Mail::Cap - Parse mailcap files
Mail::Field - Base class for manipulation of mail header
Mail::Field::AddrList - object representation of e-mail address lists
Mail::Filter - Filter mail through multiple subroutines
Mail::Header - manipulate mail RFC822 compliant headers
Mail::Internet - manipulate Internet format (RFC 822) mail messages
Mail::Mailer - Simple interface to electronic mailing mechanisms
Mail::Send - Simple electronic mail interface
Mail::Util - mail utility functions