Bread needs soaking in water as it can swell in their crops (stomachs) and make them full up but it has little nutritional value so they don't benefit much from eating it. Blackbirds and my favourite thrushes like fruit so chopped apples, dried sultanas etc; the **** and finches will enjoy peanuts, seeds and fatballs; sparrows will eat the latter as will robins but robins can't use hanging feeders very easily so will sit underneath and eat what the messy ones drop. Mealworms are super-expensive but robins love those, and suet for example. Wrens will eat bits of cheese if you leave them near hedges and fences where they might hang out. Water is very important as it freezes fast. We are lucky to have a couple of types of woodpecker here - the spotted ones can eat from nut feeders really well but the green ones want ants and when the ground is frozen they struggle.
Here is a link from the RSPB for anyone unsure, but a friend of ours is a really eminent ornithologist and says in this weather give them pretty much anything! At ours it is a toss up between our hens and the wild birds but I am favouring the latter at the moment as they are under such population pressure. It makes me really sad.
https://www.rspb.org.uk/birds-and-wildl ... for-birds/OMG the forum won't let me say the name of the little birds! T its!