waifu2x — a really great image resizer and noise reduction tool.
ezgif — literally da best gif editor ever.
html-color-codes — lets you pick colors from pictures.
blinkies.cafe — awesome blinkie maker that comes with a bunch of cool templates.
hover.css — bunch of hover effects! i used so many of these...
zingerbug — filled with free seamless, organized backgrounds. almost every background on my site comes from here.