SVGO - Tool for optimizing SVG files
Vector Artist - Vector art software designed for tablets.
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Scour - SVG Optimizer / Cleaner
AutoDraw - A Google Experiment that helps you draw with relevant suggestions.
SVGOMG - SVGOMG is SVGO's Missing GUI, aiming to expose the majority, if not all the configuration options of SVGO.