Meta.Numerics is a Mono-compatible .NET library for scientific and numerical programming. It includes functionality for matrix algebra (including SVD, non-symmetric eigensystems, and sparse matrices), special functions of real and complex numbers (including Bessel functions and the complex error function), statistics and data analysis (including PCA, logistic and nonlinear regression, statistical tests, and nonuniform random deviates), and signal processing (including arbitrary-length FFTs).
DotNetZip is a zip library for .NET and Silverlight. Using this library, you can build .NET or Silverlight applications that create, view, update, or unpack ZIP archives. DotNetZip also includes a ZLIB library and a BZip2 library. It is all managed code. Compact Framework versions of the libraries are included as well. The ZIP library supports WinZip AES encryption, regular PKZip encryption, Zip64, Unicode filenames, and many other ZIP features.