SVG and Icons should support Gradient Fill
SVG doesn't support gradient fill. Every nice icon has some sort of gradient, you should add support to it.
Gradients don't work when exporting to PDF: If an SVG contains gradients, the whole graphic will become a garbled pixelated mess upon PDF export. It's a shame this doesn't work.
If you right click and "Convert to Shape" the icon or SVG, you can do this.