Blackbirds & Thrushes
Blackbirds and song thrushes are ground feeders, and that single fact decides everything about how you feed them. Neither will use a hanging feeder. Both work along the bottom of a hedge, across a lawn and under the shrubs, turning leaf litter over for worms and insects — so food put out at head height is food they will never find.
Dried mealworms and suet pellets are the two things that make the most difference to them, particularly in a dry summer when the ground is too hard for worms, and in freezing weather when it is too hard for anything. Scatter on a bird table, a ground feeding tray, or a cleared patch of lawn, and put out small amounts often rather than a large amount at once — anything left overnight attracts what you would rather not attract.
A seed mix gives them something to work through the rest of the time. A husk-free blend is the sensible choice for ground feeding, because what a blackbird leaves behind is what sprouts in the lawn a fortnight later.
Related ranges
Much the same suits robins. Browse mealworms, suet pellets and wild bird seed.