Picture is gone

Is there somewhere a list of phones with accesible nfc contacs ?
I've got the S4 which has accesible contacts and the S4 mini which only has QI contacts.

Also a list of available antennas would be nice.
I already tried the maxfield wireless charging receiver + nfc. Which boosted nothing (no better connectivity ) but works. I am really having a hard time of finding a good antenna.

wasnt there a ring from here at the beginning that you could 3d print and put your own chip inside ?

Is there a way that i can put my own chip into the ring ? Would that require alot of tinkering ?

Hello,
Isnt there a way to boost the NFC antenna of a phone, so you dont have such a hard time finding the sweet spot?
#inductive coupling / #external antenna ?