Petra Pixel's website is very useful with self-made tutorials, scripts, code snippets, coding quizzes, widgets, layout generator, and more !

UnicodeAngel here has many links to various code snippets, templates, and widgets !

Blinkie World is probably the biggest collection of blinkies that I've seen ! What's probably hundreds of blinkies categorized by color, aesthetics, and more general categories like holidays or plants.

Itinerae here offers different layout templates (both free and paid), coded by her ! She also offers various backgrounds, dividers, stamps, buttons, and pixels. (I got my layout template from her !)

Scripted Resources is a site that offers many kinds of code snippets, image masks and animations, borders, scrollboxes, text animation, and more!

Stamp Studio is a site to make your own stamps! Just upload your image, and select any of the borders available.