Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
Create - CREATE is a powerful and intuitive mobile creativity tool.
SVGO - Tool for optimizing SVG files
Adobe Fresco - Create beautiful, scalable vector designs on your iPad with Adobe Illustrator Draw and sync your design across Adobe Creative Cloud desktop and mobile apps.
SVGminify.com - Removes superfluous information reducing the size of SVG files
Scour - SVG Optimizer / Cleaner