Scan for documents from a domain (-d kali.org) that are PDF files (-t pdf), searching 100 results (-l 100), download 25 files (-n 25), saving the downloads to a directory (-o kalipdf), and saving the output to a file (-f kalipdf.html):
root@kali:~# metagoofil -d kali.org -t pdf -l 100 -n 25 -o kalipdf -f kalipdf.html.Hunter lets you find email addresses in seconds and connect with the people that matter for your business.
Shodan is the world's first search engine for Internet-connected devices.
Find and monitor every server on the Internet
https://github.com/dafthack/MailSniper
MailSniper is a penetration testing tool for searching through email in a Microsoft Exchange environment for specific terms (passwords, insider intel, network architecture information, etc.)