Does kratos support anonymous accounts that can then be later migrated to a full account?

Not directly. There are however strategies to achieve something like it, it depends on your use case. (you can for example write a temporary session in the users cookie and then use that to prepopulate the profile on signup) In any case, as we dont seem to have an open discussion/issue for this feel free to open one: https://github.com/ory/kratos/discussions ideally give some details on your use case