Numverify - Global phone number validation and lookup API
Albacross - The world's first free B2B Lead Generation Network. Albacross help companies master their B2B digital marketing with Lead Generation and targeted marketing
Antideo - Email, IP address and phone number validation API service
Awario Leads - A real-time social media feed full of targeted leads 🔥
RealValidito - Phone Validator | Free Phone Number Validation & Phone Number Lookup Service | Realvalidito
Hunter - Find all the email addresses related to a domain