"The Mushroom Color Atlas is a resource and reference for everyone curious about mushrooms and the beautiful and subtle colors derived from dyeing with mushrooms. But it is also the start of a journey and a point of departure, introducing you to the kaleidoscopic fungi kingdom and our connection to it."
The largest (and most colorful) definitive stamps series. This huge reference of stamps is available since 1996.
The Insect Color Database is a collaborative resource designed for scientists researching insect color, pattern, and underlying mechanisms that produce these elements.
Musashino Art University's design glossary with topics like watercolor papers, japanese brushes, adhesives, and so on. Not only art topics, but some bookbinding, printing techniques.
Gary Larson's The Far Side comics + New Stuff
There are many online tutorials out there for anything. But it's hard to find a good one. Andrew Pouska's Study Bass is a gem in so many ways. Tools, well-written lessons, videos. So much content. StudyBass has paid content, but almost everything is available for free, which is unbelievable seeing the quality and the size of this project.
Actually this one is about the bad side of the internet, the stupid wild west of NFTs and crypto-scams. Really nice compilation.
A fascinating compilation of oddities, not-so-good ideas, weird stories from computer history. You can read it as a good anthology, and there are enough funny or terrifying topics for days here.
An online exhibition of the archaeological finds from the construction of the metro line under the city of Amsterdam. You can check all the finds from the last Ice Age to 2005. That's alone super interesting, but you can also check the displays inside the Rokin metro station. On top of that, they published the catalog as an oversized, beautifully designed book. Jerzy Gawronski [ed.]. Stuff – Catalogue Archaeological Finds Amsterdam’s North/South Metro Line. Van Zoetendaal / De Harmonie, 2018.
This online collection/exhibition is made in a cooperation of ten Swiss universities/institutes. You can read information about different materials, from banana fibers to various aluminum. But what I've found most interesting here is the extensive information about pigments, different paper types, and bookbinding materials. (The page is in German.)