W3Schools -- Lifesaver when I first got into web design. Gives you quick rundowns on a variety of different things.

GifCities -- A large collection of gifs
from various GeoCities sites back in
the day.

Tiled Backgrounds -- Codepen
archive of sadgirl.online's tiled
backgrounds.

RV's Javascript/DHTML
effects -- Fun little codes you can
use to jazz your site up hehe.

CoolText -- I LOVE COOLTEXT ..
Make fancy little text graphics.