Gravatar, Linktree, Bento, there are all things we could incorporate into fediverse profiles. Libravatar demonstrated that this can be done in a federated way.
Imagine when you add a new fediverse account to the profile of an existing one, it offers to synchronise your avatar, other social accounts, etc between the two. Obviously you'd have the option to say no, for each item. In case you like to have different avatars for different accounts, etc.