I’ve built a set of handy plugins for Sketch
Potrace
Convert bitmap images into monochrome vector graphics.
Reset Image Aspect Ratio
Reset the aspect ratio of selected images.
Format Symbol Names
Nicely format the names of all artboards or symbol masters on the current page.
Photo Grid
Size layers to common photo dimensions and scale them to fit in rows or columns.
Symbol Namer
A plugin to help you rename symbols. Save default values, use override text, and do powerful, pattern-based renaming.
Library Unlinker
Unlink symbols linked to a specific library, or that have been deleted in their libraries.