ARIN is the American Registry for Internet Numbers, the organisation that hands out the blocks IP addresses.
Each region has its own, for instance Australia/Pacific has APNIC. Naturally, they work very closely together.
Open Query can assist you with planning and deployment of IPv6 capabilities on your front-end servers, as well as at the back-end if you wish. Not all hosting providers support IPv6, but many good ones do. MySQL/MariaDB can operate in a native IPv6 or dual stack environment. Open Query enabled its own front-end servers for IPv6 a number of years ago already.