1) "Sales" by HubSpot - With "Sales" by HubSpot email tracking, you get live notifications when someone opens or clicks on one of your emails. You'll know when, how many times, where, and from what device they opened your email. A great strategy when using Sales to immediately call your prospect when you've been notified that they have opened your first email; what a "coincidence" that they were just looking at it the same time you called.
2) Charlie App - Charlie combs through 100s of sources and automatically sends you a one-pager on everyone you're going to meet for that day. Charlie typically sends the information 1 hour to 30 minutes before meetings and the information is around what makes them tick, what you have in common, and the critical insights on their company that hopefully your competitors won’t have.
3) TriggerFox - Get relevant alerts about the people in your networks, so you can reach out when it matters most. Get notified about job changes, birthdays, news mentions, life events, articles being shared, keyword alerts and more. TriggerFox incorporates all of your social media outlets and even lets you set VIP's and certain trigger events to track when something changes.