FLEX - An in-app debugging and exploration tool for iOS.
Chrome Mobile DevTools - Mobile Debugging Tools
Bugfender - Cloud logging for your apps, not only crashes matter
FBSonar - Sonar is a platform for debugging mobile apps on iOS and Android.
GapDebug - GapDebug is a comprehensive mobile debugging tool that bridges the gap left by other debugging options.
Spark Inspector - Spark Inspector is a runtime debugger for iOS