AngleSharp by Florian Rappl

<PackageReference Include="AngleSharp" Version="0.5.0" />

 HTMLCollection<T>

public class HTMLCollection<T> : IEnumerable<T>, IEnumerable where T : Element
public T this[int index] { get; }

Gets the specific node whose id matches the string specified by the attribute. Matching by name is only done as a last resort, only in HTML, and only if the referenced element supports the name attribute. Returns null if no node exists by the given name.

public T this[string id] { get; }

Gets the specific node whose id matches the string specified by the attribute. Matching by name is only done as a last resort, only in HTML, and only if the referenced element supports the name attribute. Returns null if no node exists with the given name.

public int Length { get; }

Gets the number of nodes in the list.

Gets an enumerator over the contained elements.