potrace - Open source program that transforms bitmaps into vector graphics.
Adobe Capture - Turn any photo into a color theme, Look, vector graphic, or unique brush that you can use in your creative projects with Adobe Capture.
Vector Magic - Easily convert JPG, PNG, BMP, GIF bitmap images to SVG, EPS, PDF, AI, DXF vector images with real full-color tracing, online or using the desktop app!
Gradient CSS - Create CSS Gradients with Ease
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
WhatFont - The easiest way to identify fonts on web pages