BATTLEFIELD 3 ORIGIN (NOT AMAZON PRIME)
BATTLEFIELD 4 ORIGIN (NOT AMAZON PRIME)
You know all Battlefield game keys you can get now days activate on Origin? Plus I'm not aware of them having gave keys out for 3 & 4 on Prime.
They gave out Battlefield 1 & Battlefield 5 recently however the Battlefield 1 keys have expired; the Battlefield 5 keys expire at the end of September if not used. (Both stay in your account once you use the serial of course.)
Even Steam copies, which don't give you a serial you can see I don't believe, make use of Origin.