Hunter - Find all the email addresses related to a domain
TagSpaces - TagSpaces is an open source platform for personal data management. With TagSpaces you can manage and organize the files on your laptop, tablet or smart phone.
Find Email Address - Highly Accurate Email Finder and Verifier
allTags - allTags is a free, tag based file management application.
Snov.io - More leads. More sales. More revenue.
Elyse - The free version allows up to 30 tags.