Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
SpamAssassin - Use this program to "Unspam" your mailbox(es).
SpoofCard - Disguise your Caller ID
Mailwasher - Over 8 million people use MailWasher as their spam filter
Mail Dump - Powerful Extensions for email addresses extracting, verifying and finding
Spamihilator - The free Anti-Spam-Filter Spamihilator removes more than 98% of spam mails before they even get into your inbox.