Which IPv4 address type conserves the pool of globally unique addresses?

Private IPv4 addresses conserve the pool of globally unique addresses because they are not routable on the public internet. Organizations can use these addresses internally without needing to register them, and they can be reused by many different organizations. Network Address Translation (NAT) is then used to allow devices with private IP addresses to access the internet using a single public IP address. Loopback addresses (127.0.0.0/8) are used for testing the local network interface and don't conserve public addresses. Multicast addresses (224.0.0.0/4) are used for one-to-many communication and also don't conserve public addresses. Public IPv4 addresses are globally unique and routable on the internet, so they are the ones being conserved.