Based on our record, Facebook Design Resources seems to be more popular. It has been mentiond 2 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Spotify isn't doing anything unique here, and it's not really a marketing campaign to explain away their UI. It's more of a showcase for hiring professionals, developers/designers/etc. Facebook has a similar one -> https://design.facebook.com/. Source: almost 3 years ago
Also, read anything published by Design @ Facebook. Source: about 3 years ago
Don't Make Me Think - Originally written in 2000, Don't Make Me Think is one of the original books on web design and usability. Although it's been around for a while, the goals and lessons of the book are universal and apply to websites today.
Designer Mill - Collection of Best Free Design Resources
The Design of Everyday Things - A timeless book, The Design of Everyday Things explores the fundamentalprinciples behind all design, and how to understand the psychology behind how we use things, and why they frustrate us.
Interfacer - Collection of more than 200+ free design resources
Coursera - "Compilers" by Stanford - The course explores how high-level languages are compiled to low-level assembly.
Freebiesbug - Collection of the best free web design resources.