YourKit .NET Profiler is described as 'YourKit Profiler provides zero-overhead profiling for your .NET applications and makes code profiling and memory usage optimization simple and fast'. There are nine alternatives to YourKit .NET Profiler for Windows, Linux, Mac, BSD and .NET Framework. The best alternative is Apache NetBeans, which is both free and Open Source. Other great apps like YourKit .NET Profiler are VisualVM (Free, Open Source), .NET Memory Profiler (Paid), dotTrace Memory (Paid) and ANTS Memory Profiler (Paid).
VisualVM is a visual tool integrating several commandline JDK tools and lightweight profiling capabilities. Designed for both production and development time use, it further enhances the capability of monitoring and performance analysis.
dotMemory allows you to analyze memory usage in a variety of .NET and .NET Core applications: desktop applications, Windows services, ASP.NET web applications, IIS, IIS Express, arbitrary .NET processes, and more.