Antideo - Email, IP address and phone number validation API service
Numverify - Global phone number validation and lookup API
Verifier - Weed out disposable, non-existent domains or invalid emails.
RealValidito - Phone Validator | Free Phone Number Validation & Phone Number Lookup Service | Realvalidito
Proofy - Quickly validate and verify your email lists.
Veriphone - Phone number validation & carrier lookup