Here's my go to seed:
Corn (cracked and whole) - keeps doves and starlings away from my other seed and squirrels. Makes a good cheap feed for any of the birds, they'll all eat it.
Black oil sunflower - cardinals, Jay's, finches, titmouse, everyone loves these!
Safflower seeds - cardinals, titmouse
Nyjer - Goldfinch and house finches
Shelled peanuts- Bluejays, red bellies
I find that if I buy seed by itself and not a mix, I have less waste. Birds aren't picking through a mix finding what they want.
Also I can put the corn in a platform feeder away from my other seed and I see less starling traffic.