Option 1: "6to4" https://en.wikipedia.org/wiki/6to4

Option 2: "nat64" https://en.wikipedia.org/wiki/NAT64 + DNS64

Option 2b: "nat46" (which makes a few ipv6 hosts available over ipv4 if yo ulike)

Option 3: "Teredo" (also known as "6in4" "tunnel broker" "6over4" "tunneling" ...) https://en.wikipedia.org/wiki/Teredo_tunneling

Option 4: 6rd https://en.wikipedia.org/wiki/IPv6_rapid_deployment

Option 5: ffff/96 (yes I get it, only works if host has both ipv4 and ipv6, on the plus side: no need for the network to support it. Mostly for applications)

Option 6: DS-lite https://en.wikipedia.org/wiki/IPv6_transition_mechanism#Dual...

And then there's the weird ones: https://en.wikipedia.org/wiki/IPv6_transition_mechanism

The issue is most of these require ISPs to deploy new hardware, or deploy new network services. The problem is that network hardware is single-purpose, because only single purpose hardware can sustain the speeds we demand of internet networks. This means a lot of hardware needs to be replaced in order to make the global IPv6 transition and, short of redesigning IPv4, which is 43 years old now, there's no other way to make the transition. All these solutions require either work by your ISP, or work by you yourself on all your hosts.