css

cssgradient — css gradient generator
cssmatic — css box shadow generator
hover.css — bunch of hover effects, i used to use so many of these...

backgrounds

zingerbug — filled with free seamless, organized backgrounds. almost every background on my site comes from here.
asadal — where the original frutiger aero backgrounds came from.
pictures.4ever — lots of early 2000s-looking backgrounds.

other

waifu2x — a really great image resizer and noise reduction tool.
ezgif — literally da best gif editor ever.
photopea — free online photoshop alternative, great for making blinkies from scratch.
dafont — free fonts online, nearly all of the fonts on this site come from here.
remove.bg — remove backgrounds from images for free, kinda insane how good it is.
html-color-codes — lets you pick colors from pictures.
blinkies.cafe — awesome blinkie maker that comes with a bunch of cool templates.
webestools — a userbar generator.
grid-layoutit — grid layout generator

metal-archives — a metal band encyclopedia.
occult-world — epic occult database.
yokai — japanese yokai database.
kidpix — online version of kidpix.
jose-hernandez — the portfolio of an oil painter i really like.
vocaloid lost media — playlist of lost vocaloid songs (i hope someday we will be able to find interface...).
webcamtoy — take fun pictures with your webcam.
marriage certificate generator — get married to ur favorite character.