EasyRGB - The inimitable RGB and COLOR search engine!
Computers, Graphics, Web, Colors - Easy RGB. Match RGB and color data to real products and color collections.
https://www.easyrgb.com/en/
Colors
Web Color Chart - Hexadecimal - by VisiBone
Computers, Graphics, Web, Colors - HTML Color Codes. All 216 web safe hexadecimal HTML color codes arranged by hue in a one-screen color wheel.
https://html-color-codes.com/
VisiBone
Web Design Reference Guides: Color, HTML, CSS, special characters, etc. Posters, charts, laminated cards, mouse pads. Free online: color scheme lab, color-wheel swatch libraries, color tables, character references.
http://www.visibone.com/