Top 20 NuGet diff Packages

Comparer for arbitrary object graphs
Find the difference between two sequences of entities in Azure Table Storage
A library to help with .NET API development and and NuGet diff-ing.
Calculate a diff between any two lists and optionally merge them to aid in synchronizing data.
A class library for comparing two text files with the ScintillaNET control.
DiffPlex is a diffing library that allows you to programatically create text diffs. DiffPlex is a fast and tested library.
A library for producing diffs of images with highlighting.
Simple Object Comparer that generates a Diff between objects and is able to Patch one object to transforms into the other. Uses Newtonsoft Json.Net for Diff and Patch. Note: this nuget package contains C# source code and depends on .Net 4.0.
Diff.Match.Patch is a port of google-diff-match-patch.
This is the .Net Standard port of https://github.com/richclement/ImageDiff . Sadly I did not get in contact with him so I'm publishing this.
Extensible diff library for text, json and XML
A utility that runs in the windows tray and handles the results of file differences.
A CSharp library that allows you to diff two objects and get a list of the differences back.
Finds the differences between two xml files.
DeltaQ provides fast and portable delta encoding for .NET in 100% safe, managed code
Object Diff (object-diff) binding library for Bridge.NET projects.
Wad of stuff. See also: RT.Util, RT.Serialization.Json / RT.Serialization.Xml, RT.Json, RT.PostBuild and RT.Util.Legacy.
Managed VCDIFF decoder for .NET
AutoCompare is a simple library with the goal of making it effortless to compare two objects of the same type to generate the list of modified properties.
C# implementation of the Diff algorithm