Yes, the primary thread is here; Making payments with an implant - FAQs - Dangerous Things Forum
Removing a payment chip from a card and placing it into an implantable bioproof package should be possible, but it depends on a couple things - primarily if your payment card is a dual interface chip or if the contactless chip is separate from the contact chip. Dual interface chips can be extremely difficult to re-encapsulate because the silicon chip itself is not in a workable package, but instead is wirebonded to antenna leads and a goop adhesive is dabbed overtop, so the final package size includes the contact surfaces on the top, and antenna connections on the bottom. That drastically increases the size of the package that needs to be bioproofed and made implantable. In short, I have done this in the past with US payment cards which have a separate contactless chip or no contact chip at all, but I have not successfully done this with a dual interface chip… it’s very difficult.