I have looked around, myself, but not found a FOSS alternative. There are typically compliance issues like PCI DSS for certain banks that prevent trust and cooperation from those banks outside a larger entity like Google, Apple, etc.
Aside smart phones, Flipper Zero can clone some cards sucessfully. But that’s an entirely different device, not an app for a phone. Best of luck!
Alternatives list on a Reddit post –
Teddit:
https://teddit.net/r/SimpleMobileTools/comments/18929pq/simplemobiletools_was_sold_alternatives/
Reddit orig:
https://www.reddit.com/r/SimpleMobileTools/comments/18929pq/simplemobiletools_was_sold_alternatives/