AndriyKozachuk 

Contains Verify - fast and extensible class for simple method arguments asserts. Example: Verify.Args(new { param1, param2 }).NotNull()

IntX is an arbitrary precision integers class written in pure C# with fast - about O(N * log N) - multiplication/division algorithms implementation. Runs on .NET 2.0+.

FasterTests is a parallel unit tests console runner for NUnit