Illustrator Script - Batch Export Symbols as PNGs

ExportSymbolsAsPNG.jsx

var doc = app.activeDocument;
var symbolCount = doc.symbols.length;

if (symbolCount >= 1) {

    if (confirm("Are all your layers hidden?")) {

        // choose directory
        var dest = Folder(doc.path).selectDlg();

        // folder chosen
        if (dest) {
      
            // create temp layer
            doc.layers.add();

            // loop through symbols
            for (var i = 0; i < doc.symbols.length; i++) {

                // place a symbol instance - temp
                var symbol = doc.symbolItems.add(doc.symbols[i]);

                // assign name
                var filename = (doc.symbols[i].name)

                // export symbols
                savePNG(dest, filename);

                // delete temp symbol instance
                symbol.remove();
            }
            // remove temp layer
            doc.layers[0].remove();
        }
    }

    function savePNG(dest, filename) {
        // save options
        var type = ExportType.PNG24;
        var options = new ExportOptionsPNG24();
        options.transparency = true;

        // file
        var file = new File(dest + "/" + filename);

        // export
        doc.exportFile(file, type, options);
    }

} else {
    alert("You don't have any symbols in this document");
}

Note: This script seems to have issues since Illustrator added dynamic symbols. I wouldn't recommend using it.