Working on the early Marvel animations there are a ton of uncredited guest stars near enough in every show pre-X-Men. Animation as a whole seems to be doing this as Krypto the Super-dog would just credit "Stars" (even if they appeared in 9/52 episodes of a season) and then 'Featured Voices' (A list of the guests that appear over the entire season, but also not featuring some recurring actors at all).
Obviously over time various sources have been able to define who played certain guest roles, however a lot of characters still don't have an actor assigned. I'm suggesting we are able to create a new role type for guest stars which doesn't require the actor field to be filled in, so that the character is still assigned to the episode and if the information is then available one day for that role a user can simply change the field and fill in the actors name.


