For all practical purposes, white millet and black oil sunflower seeds will attract all of the seed-eating birds that you are likely to see at your feeders. Birds such as sparrows (chipping, white-throated, fox, field, white-crowned, and song) dark-eyed juncos, mourning doves and eastern towhees all relish white millet. Even cardinals devour their fair share of these seeds.
The long list of birds that prefer to dine on black oil sunflower seeds includes cardinals, house and purple finches, Carolina chickadees, white-breasted nuthatches, blue jays, red-headed and red-bellied, downy, and hairy woodpeckers, American goldfinches, and pine siskins.
In order to attract these and other seedeaters offer seeds placed on or near the ground as well as elevated feeders.
Between those two seeds and a high quality suet, I see just about everyone here (except frugivores)