Here are some of features of Design Arsenal which are not available in Icon Drop:
Fonts catalog: install fonts directly from our catalog of fonts, no need to download/install them
Magic font layer creation: create a font layer in Photoshop, Illustrator or Sketch in a single-click... font is installed automatically
Free SVG icons: searching and using free SVG icons has never been easier... our app comes with many icon packs like Material Design
Pattern manager/catalog: manage your own local pattern images or use one from our catalog
Magic fill layer from pattern: just right-click a pattern and choose to create a filled shape in Photoshop or Sketch
Link organizer: save your favorite design sites so you never miss them
Wanna know the human factor behind it?
The creation of this product is a single person big endeavor, and I am trying to share my experience in bringing it to life.
This way you might be able to give your thoughts and participate in the development process.