If you need icons or sounds you can always extract them from existing themes using p3textractor. If you do this, make sure you give credit to the original creator in the theme description.
There's always the diy method using Photoshop or Gimp for icons. You can search the internet for sounds. There are tutorials here to help you with putting sounds into themes.
Of course there's some searching involved, but that's part of the fun of theme making.