Doesn't actually download anything, but saves all svgs from Iconmonstr by grabbing each inline svg from the preview box. If you like the Icons please consider to make a donation for the iconmostr wesbite - http://iconmonstr.com/

iconMonster.js

var casper = require('casper').create();

var fs = require('fs');
var pages = [];

casper.start('http://iconmonstr.com/page/2', function () {
  var pageNumbers = this.evaluate(function () {
    return $('a.page-numbers:nth-child(7)').html();
  });

  for (var i = 1; i <= pageNumbers; i++) {
    pages.push('http://iconmonstr.com/page/' + i);
  }

  this.each(pages, function (self, page) {
    self.thenOpen(page, function () {

      this.echo(this.getCurrentUrl());

      var fileNames = this.evaluate(function () {
        var tempArray = [];
        $('.thumbnail-link').each(function () {
          var name = $(this).attr('href').substring(22);
          name = name.substring(0, name.length - 1);
          tempArray.push(name + '.svg');
        });
        return tempArray;
      });

      var inlineSvgs = this.evaluate(function () {
        var tempArray = [];
        $('.thumbnail-preview').each(function () {
          tempArray.push($(this).html());
        });
        return tempArray;
      });

      for (var i = 0; i < fileNames.length; i++) {
        inlineSvgs[i] = '<?xml version="1.0" encoding="utf-8"?>\n' +
          '<!-- License Agreement at http://iconmonstr.com/license/ -->\n' +
          '<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">\n' +
          inlineSvgs[i];
        fs.write('svg/' + fileNames[i], inlineSvgs[i], 'w');
      }
    });
  });
});

casper.run();

Thanks for snippet!