esim.me, 9esim and "sysmocom eUICC for eSIM" are eSIMs in the SIM card form factor that you can load the SIM profiles onto and use them in any device with a SIM card slot (and of course transfer between devices). In my opinion, that's the best of both worlds.
> It's good, but they're expensive as fuck for what they are.
Yep, I remember a time where you could extract the Ki and IMSI from legit SIMs and write that to a bog standard Goldwafer card (which were also used for cable TV hacking) including some SIM emulation software and thereby clone the SIM. That was like 30 years ago and the only thing that changed in SIMs since then is better encryption.
