TouchStream - Drip campaigns for Gmail
Email Studio for Gmail - Send personalized emails, schedule emails directly in Gmail
Signature.email - A powerful visual drag and drop email signature generator paired with the easiest way to maintain consistency for your whole team.
EmailDrips - Get inspired by examples of email sequences
Elite Email - Drag & drop email builder for awesome newsletters
Clearbit Salesforce - Rapportive for Salesforce, augment lead data