Your coin is good, but a card would be better ( also likely thinner ) I carry a T5577 Card in my phone case, as a test card, and a backup for if I come across a stubborn reader.
And yes, an implant is COOLER 
A perfect excuse to get the ApexFlex
I am assuming you have been on the Fidesmo App store to get your OTP setup.
You would have seen some other options there also.
If you are familiar with OTP, you are on track for learning how to use the other.
REMEMBER though, you are an early adopter and there are still things being worked on in the background.
Of course there is the obvious but very usable NDEF option too.
you will be referring to the Version 2 of them, but you have to wait until Soon™
If you want Blinkie, you currently have xSIID to fulfil that.
They are reasonably common, especially the NTAG213 in sticker format ( i.e. Disposable )
You will find, the more things you scan, the nore you will realise how much RFID ( LF & HF is out in the wild )