Epieos - Retrieve information linked to an email address, without notifying its user.
Ignorant - Ignorant allows you to check if a phone number is used on different sites like Snapchat, Instagram.
Holehe - Holehe checks if an email is attached to an account on sites like Twitter, Instagram, imgur and more than 120 others.
OSINT Industries - OSINT-powered tools for email and phone number investigations.
bitwarden - Bitwarden is a free and open source password management solution for individuals, teams, and business organizations.
Snusbase - The industry leading database lookup.