LogTailApp - LogTail is a local and remote (SSH) log file viewer and monitoring application for Mac OS X. It is a pure, modern, document-based Cocoa App
Serilog - Backend Development and Utilities
AppSignal - We monitor the software that makes your customers happy.
NLog - NLog is a free logging platform for .NET with rich log routing and management capabilities.
Hawk - Hawk provides visual user tracking and error reporting with live screen view, deep filtering and robust access control.
ZeroLog - ZeroLog is a JSON logging library that allows you to log messages in a structured, searchable, and easily parseable format and allow for customizable output.