Facebook Design Resources VS Atlassian Design

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

Atlassian Design System: Atlassian's Design System encompasses a color module encompassing primary, secondary, and functional colors, along with an extended palette for shades and tints. The system provides comprehensive guidelines for effective color usage and emphasizes accessibility. - Source: dev.to / 8 months ago

Atlassian design system: https://atlassian.design/. Source: 12 months ago

Regarding discoverability, you could build a directory with documentation. Similarly to how design systems are documented, e.g: https://atlassian.design/ But if you really want to share them you'll probably need to evangelize it somehow. Source: about 1 year ago

Step 5: Study design system Atlassian design system Primer design system Spectrum, Adobe’s design system Carbon design system. - Source: dev.to / about 1 year ago

Have you checked out https://atlassian.design/ and https://www.atlassian.com/team-playbook? They're pretty good. Source: over 1 year ago