This collection is part of ShapeChef, which you can download here. ShapeChef is an add-in that integrates itself into the PowerPoint window. To install ShapeChef, you will need PowerPoint 2007, 2010, 2013, 2016, or 2019 for Windows.
Once you have installed ShapeChef, simply click on the large Download More Shapes button. You can then browse all available collections and download the ones you like.