PSD3 & PSR
PSD3 (the third Payment Services Directive) and the accompanying Payment Services Regulation (PSR) are the European Union's proposed successors to PSD2, intended to fix its uneven execution — tightening API performance and access requirements, curbing fraud, and moving core rules into a directly-applicable regulation to reduce national divergence. As proposed legislation they set the near-future direction of European open banking and open finance.
Countries
Where this binds. Each links to the providers apis.io has catalogued there.
Industries
Each links to that industry as a scored cohort — so the question "how ready is this sector for the regime that governs it?" becomes one you can actually look at.
Implemented by these standards
A regulation is the law; a standard is the machine-readable contract that satisfies it. Almost every regime in this catalog restricts an interface rather than requiring one — where a standard exists, it is the part a provider can actually publish.