Sentry.io - From error tracking to performance monitoring, developers can see what actually matters, solve quicker, and learn continuously about their applications - from the frontend to the backend.
Bugsee - See video, network & logs leading up to bugs or crashes
TrackJS - JavaScript Error Tracking for Modern Web Applications
Buglife - Seriously awesome bug reporting for iOS apps
Rollbar - Rollbar collects errors that happen in your application, notifies you, and analyzes them so you can debug and fix them. Ruby, Python, PHP, Node.js, JavaScript, and Flash libraries available.
Instabug - The top apps in the world rely on Instabug for beta testing, user engagement and crash reporting.