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
Cozi - Cozi | Must-have app for the modern family
Designer Mill - Collection of Best Free Design Resources
Google Calendar - Spend less time managing your day & more time enjoying it
Interfacer - Collection of more than 200+ free design resources
OurHome - Stay organized as a family with synced calendar, chores and more.
Freebiesbug - Collection of the best free web design resources.