The ability for a user of two packages to tell Julia to merge is being investigated in https://groups.google.com/forum/?hl=en#!topic/julia-users/sxXuTiOrA_M which would obviate the need for "verbs in base".
This does not change the OPs question about what are the "standard" verbs that a type needs to behave like another one. Something like Haskell typeclasses might be useful.
