Monotone Icons
Vault needs icons. I've been working on this set for a while now.
The icons are designed to be used as masks, so their color can be changed easily for state changes within the UI. They're also 16×16, maximum, with 1px strokes, aligned to the pixel grid.
Details inside the icons' outline can use opacity for fills and strokes to add variety to the set. The opacity scale is in 20% increments.
In total there are hundreds of icons including file types, folders, media player controls, arrows, and all of the other icons commonly used in application design.
Image: A few of the icons from the Monotone Icon Set.