You can get your own autonomous system, and take your IPs with you when you change ISPs, or have the same IPs reachable through multiple ISPs. This is possible

You can get your own autonomous system, and take your IPs with you when you change ISPs, or have the same IPs reachable through multiple ISPs. This is possible for both ipv4 and ipv6 but ipv6 is much cheaper. Still not really something that makes sense for a residential user. You need to have networking gear that handles routing on the internet, bgp advertisement instead of having your ISP handle it. There are annual fees, you generally need to be on a business plan with the ISP. For ipv4 the minimum ASN size is a /24, it costs around $12k to buy the IPs for a /24. Ipv6 ips are free. It also costs around $1000 in annual fees for an ipv4 asn, ipv6 is less. ipv4 ASNs smaller than /24 aren't advertised outside of your current ISP and aren't really portable. Currently there are about a million ipv4 prefixes advertised. And about 150k ipv6 prefixes. Some older ipv4 equipment has a limit of 1024k, or near 1 million advertised prefixes. This equipment is usually 15+ years old, but still is what runs the internet. Generally equipment that supports ipv6 can support many more networks