Anima App - Design, get feedback, convert to code, publish, iterate.
IcoFX - IcoFX is an all-in-one solution for icon creation, extraction and editing.
Sketch Repo - Collection of resources for anyone who uses Sketch
icon sushi - @icon sushi is icon converter that supports xp icons, vista icons, bmp, png, psd, exe and icl.
Git Sketch Plugin - Version control for designers
Icon Slate - Icon Slate lets you easily compose, import and export desktop icons in many formats.