WiseStamp - WiseStamp allows you to easily create and implement slick and unique email signatures for your business.
NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
MySignature - MySignature is FREE Email Signature Generator that helps to create Professional Signatures for major email clients such as Outlook, Gmail...
Email Verifier - Email verifier app lets you verify email.
Sigstr - Email signature marketing
Verimail - Clean up email-address lists of any size or use our powerful API for real-time verification.