Unless you know your land, not much.
There is too much snow to see the last remaining greenstuffs, like nettles and the cresses. The ground is frozen solid to about 15 cms here, so digging for roots, even when you know where they are, isn't fun. Few withered and frozen rosehaws and rowans and that's about it for the fruits. Same for the jelly ear fungi, shrivelled to nothing, and no others about.
Sea veggies are still possible,just, and if your ponds are clear; ours aren't, they're frozen solid too; then cattail roots would be good.
Toasted and ground tree barks, if you can prise them off the trees, no sap rising, no buds opening. Pine needles for tea. Mosses are frozen solid too. The oats, barley and wheat I left on the stalks to see have mostly spilled their seeds and the birds got them. The lemon balm still has some leaves low down so I've been using some of them for tea, sage and thyme since I know where they are under the snow. Some of the Docken stems still have seed heads.
What have you found ?
cheers,
Toddy