NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
Short - The reading list for busy people
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
7reads - A minimal mindful reading list for Google Chrome.
DeBounce - Email Validation, Email Checker, Data Enrichment and Appending Tool. Using DeBounce remove invalid, disposable, spam-trap, syntax and deactivated emails.
Votum for Slack - Crowdsourced lists with upvotes, inside Slack