ZenLulz 

A lightweight library for benchmarking performance of your .NET applications. BenchShark provides a powerful and easy to use API to evaluate the speed of your functions in order to track down the bottlenecks... More information

A managed wrapper to use FASM compiler within .NET applications.

MemorySharp is a C# based memory editing library targeting Windows applications, offering various functions to extract and inject data and codes into remote processes to allow interoperability.