European Union
Mandatory fingerprinting of citizens
Regulation (EC) 2252/2004 and Regulation (EU) 2019/1157 mandate that all biometric passports and identity cards issued by EU member states must contain at least two fingerprints. The United Kingdom and Ireland - both outside the Schengen free travel area - were given opt-outs.
Conveniently, a lot of European countries also mandate that everyone must have an ID card. Even without this, one of these identity documents is generally required to cross internal EU borders, and the majority of people get a passport at some point. This effectively means that all citizens are legally required to have their fingerprints taken.