SIREN.io - Siren is an investigative intelligence platform.
Spybot Identity Monitor - Get an overview where your account was leaked.
Lampyre - Lampyre - an efficient data analysis and OSINT multi-tool for everyone.
Snusbase - The industry leading database lookup.
Netglub - Netglub, the really open source information gathering solution.
LeakCheck - Data breach search engine, low price starting from $10/mo, one email address for free, unlimited API, 7B+ entries