Hi, Veggiemama - great name- welcome to GoY!
Salad leaves, lettuce, winter spinach, radish, parsley? You could start beans and peas for planting out later.
Others will have suggestions, too.

At this time of year I would suggest the following, which can be bought in seed packets ... land cress, pak choi, winter density lettuce, rocket, winter hardy spring onion, winter radish. All these can be sown now, and either sown directly into your veg plot for early cropping in spring, or grown in pots in your greenhouse. Beware the current mild weather, and give lots of ventilation. Keep soil only very slightly moist to avoid rot, mosses etc. You could even try a deep tub of carrots, parsnips and some early potatoes - it all depends on your space, as trays won't work. I have carrots in a tub, and a bin of parsnips and potatoes coming up every year at this time. Cold weather stops them for a while but they always seem to come through it. Garlic and onion sets should be planted out immediately for harvesting next summer. Suggest starting peas and beans next spring before planting out.

Many thanks for the information and the welcome.

Welcome to GoY.