unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, System.Generics.Collections, Card;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    FCards: TObjectList<TCard>;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
  I: Integer;
  Card: TCard;
begin
  // create a collection instance
  FCards := TObjectList<TCard>.Create;
  // loop to make 20 cards
  for I := 1 to 20 do
  begin
    // create a TCard instance and set whatever you need; this variable will be
    // overwritten, but in this case without a leak, because we're passing it to
    // the collection, which will keep the reference to the created instance and
    // can even free it for us
    Card := TCard.Create(nil);
    Card.Parent := Self;
    Card.Left := I * 50;
    Card.Top := 8;
    // do whatever else with a Card instance and then add it to the collection,
    // but DO NOT FREE IT! now the collection itself is responsible for that and
    // if you want to ever access this instance, you can't release it now
    FCards.Add(Card);
  end;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  // and if you free the collection which owns the objects, it will release all
  // the TCard instances we've made before
  FCards.Free;
end;

end.