Technically, it’s resource_get_tablename, but the first usable event is controller_front_init_before.
But this is also a bit of a trick question. controller_front_init_before is ONLY triggered from the global area. The first usable event in the frontend (or adminhtml) area is controller_action_predispatch. core_locale_set_locale might also be a possibility because it is set when the area is loaded, but I would say that controller_action_predispatch is still the best, first usable event once the area is known.