SharpShooter Diagrams offers a unified designer for diagrams and flow charts building which can be integrated into Silverlight app. It includes 200 predesigned shapes that are complex objects with properties setting up their appearance and behavior.
Downloads: 37728 - Shareware - Download Now

Altova SchemaAgent is a graphical tool for analyzing and managing XML Schema, XML instance, XSLT, and WSDL file relationships across a project or an enterprise. Visualize and easily manage file associations via its graphical design interface.
Downloads: 47434 - Demo - Download Now

A collection of scalable icons for use on toolbar/ribbon buttons and similar user interface elements.
Downloads: 60008 - Freeware - Download Now

IronXL - The C# .NET software library for .net software coders to read, write, edit Excel Spreadsheet documents in .NET apps & websites. It is available from https://ironsoftware.com/csharp/excel/ or https://www.nuget.org/packages/IronXL.Excel/
Downloads: 3613 - Shareware - Download Now

We can easily use IronExcel to read Excel files in any C# or VB .NET application, including those developed with .NET Framework, Core, and Standard. We use IronExcel to read in an XLS or XLSX file and can then manipulate the data, including formulas.
Downloads: 1711 - Shareware - Download Now