This company, Sierra Wireless also sells SIM cards. In fact they sell a sampler of the currently available names such as Verizon and T-Mobile. They are all described such as:
https://shop.sierrawireless.com/ccrz__P ... clcl=en_USLTE SAMPLE PACK
SKU LTESamplePack
Test your device(s) on all of Sierra Wireless' LTE connectivity offers. Choose the data bundle at SIM activation. Manage all four connectivity options on Sierra's AirVantage portal, which is included with your activation.
Device(s) must be compatible with the respective technology; LTE
All applicable certification requirements must be met (Verizon, AT&T, T-Mobile, Sierra Wireless, PTCRB)
All Enhanced Carrier Connectivity SIMs are triple cut
You will receive one of each (2FF, 3FF, 4FF) SIM for Smart Connectivity.
Obviously they expect the buyer to be using their hardware, but currently the FONA platform is in my budget. Let's just say I'm exploring the sky of blue for an idea concerning the FONA Feather and an RP2040 Feather.