Top 20 NuGet unity3d Packages

GladNet3's (Glader's Library for Advanced Development of Network Emulation Technologies) crypto API. Install this package if you need to implement a cryptographic implementation to be used in the GladNet3 networking.
The probably fastest way to use custom contracts in Photon
Dependency injection tools for Unity3d.
UnityRefAnalyzer
This package adds formatters for all the types in the System.Collections.Immutable namespace. For example ImmutableArray, ImmutableSet, ImmutableDictionary, ...
A mapping SDK to visualize 3D cities and terrain in Unity. See project site for more details.
Tool for Unity NuGet packages
The package of Cascade library. It allows to read text files and convert to hierarchical tree format.
Roslyn analyzers for Unity game developers