Having spent the past couple years working on a large design system, I am most excited about @react-aria and @react-stately. There is huge potential for allowing resource constrained teams to build out a truly customized DS in a fraction of the time. Even for a well resourced team, these hooks can make extending their existing DS and borrowing complex behavior much simpler/faster. The biggest challenge for a DS at scale is in how you can adapt it to the infinite edge cases that a product eventually uncovers- while staying consistent and leveraging existing code. I think these libraries offer the best model yet for achieving this. Congrats to @devongovett and the team at Adobe for realizing these ambitious projects and successfully open-sourcing them.