The Mysteries Revised has a list of widely known arcana. How are these initiated? Do they use initiation scripts with Magic Lore/Magic Theory as the Cult Lore or is there some other system? I recall that apprentices can "absorb" a virtue from their parens from simple exposure but I thought that was more for affinities and puissant *. Is this also used for things like planetary magic?
"Curious Common Magics" can be initiated using the normal rules for such things, but as the title suggests, are already widespread in the OoH as a whole and so are appropriate for use by starting characters without, necessarily, requiring the "Cabal Legacy" flaw.
They are probably often "taught" via the rules in apprentices rather then initiated.