How to exclude/not display .NET Framework packages in Nuget?

Question

I am building .NET applications on .NET 4.5.2 or 4.6.2, and not use .NET Core. When updating NuGet Packages in Visual Studio 2015, The Updates tab lists a few dozens packages that are parts of .NET Framework such as System.IO and System.Linq.

Is that good to include/store those packages in the packages folder, in every VS solution folders?

Can/should I just use .NET Frameworks that had already been installed?

Is there a way not to display those .NET Framework packages in the Updates tab of NuGet VS?

Apparently after updating to the latest xUnit.NET v2.2.0, NuGet VS starts to promote 31 updates, as shown in this screenshot. But I don't use them.

Answer 1

According to Brad Wilson one of the key authors of xUnit.NET, "The minimum version of .NET required for desktop CLR unit tests is now .NET 4.5.2. " at https://xunit.github.io/releases/2.2

Updating the test project from 4.5 to 4.5.2 then updating to xUnit.net 2.2 won't introduce .net core. And my others test projects that had started on 4.5.2 or 4.6.2 before xunit 2.2 had never promoted for .net core updates.