The original Finnish one was TUPAS, it has been available since at least 1998. It was phased out in 2019 as it was not compatible with eIDAS. For end users there isn't really any difference but the old system required separate contracts between each bank and service provider. Due to that service providers also couldn't use 3rd party (think service like Auth0) who would handle contracts with individual banks. From my understanding it was also fairly expensive (in terms of per authentication event). The new one is called Finnish Trust Network and uses OIDC and in some cases SAML, TUPAS had it's own protocol (I'm not sure if there even was a standard protocol for that kind of authentication back then, even SAML 1.0 came out only in 2002).