Now Push Notify - iOS does not support browser notifications today, but Now Push Notify makes this possible.
Pusher Beams - Send push notifications programmatically at scale
F5Bot - F5Bot will send you an email whenever your brand, product, or keyword is mentioned online.
PushNinja - by 500apps
Push Notification Preview - A simple tool for previewing push notification copy
Analyzify - Google tag manager and analytics app for your Shopify store