Synder - AR Automation
Unlimited Email Tracker - Track opens and clicks, set reminders and delays in Gmail
Codat - Codat works with lenders, banks, insurers and software providers to provide integrations with the accounting and other financial softwares.
Mailtrack.io - The best email tracking solution I've found. Free
Railz - Build Financial SME apps using normalized Accounting data
EmailTrackerPro - EmailTrackerPro is an email tracking and spam filter solution.