Syncerize - Effortless Product Import, inventory sync, and order update
Essential Goods - Know immediately when an essential you need is back in stock
SEO Minion - Chrome extension & Firefox add-on to help you with SEO
Shopper.com - Uber for Coupon Codes
Nightout - The standard in event ticketing and marketing by NIGHTOUT
OctoShop for Chrome - Compare prices and get alerts when things are back in-stock