Top 20 NuGet addinmodel Packages

Core CSOM extension methods for SharePoint Online add-in model development. This will increase productivity of the developers by abstracting complex operations.
Core CSOM extension methods for SharePoint 2016 add-in model development. This will increase productivity of the developers by abstracting complex operations.
Core CSOM extension methods for SharePoint 2013 add-in model development. This will increase productivity of the developers by abstracting complex operations.
Core CSOM extension methods for SharePoint 2019 add-in model development. This will increase productivity of the developers by abstracting complex operations.
A port of Microsoft.IdentityModel.Extensions.dll packaged as a NuGet package by the SharePoint PnP team.
The AweCsome-Framework is like an Entity Framework for SharePoint Provider Hosted Add-Ins. It uses CSOM to communicate with SharePoint.