You duplicated some vector images with other dimensions. There's no need to do this. Vector images are with best quality in any sizes always.
Favicons are duplicated. It may be useful to have images for different sizes if image in smaller containers should look differently. For example, application icon on iPad are with 512px/512px. But they're may have less details in picture when they're in favicon 16px/16px. But in out project icons are the same so you can remove not used images.
The same about some icons with folders named by their size. SVG can be scaled lossless, so you don't need to declare sizes. It's not restricted, you may use it to declare some system in your folder names, but it's useless in terms of difference between raster and vector images.
You have different files for arrows images, but they're look the same. So you can store only one of them and switch direction of arrow via CSS.
You duplicated some vector images with other dimensions. There's no need to do this. Vector images are with best quality in any sizes always.