Lemons and limes, slice and freeze for drinks, or juice into ice cube trays and freeze then use in those recipes that call for a tablespoon or squeeze of juice.
Fruit, slice and freeze it, even if it's just 1 apple or a handful of blueberries. Chuck it all into the same bag in the freezer and use as smoothie mix or crumble filling.
Late summer and autumn we have a huge glut of raspberries and blackberries in our garden, then plums from MIL. We spend an afternoon making various combos of fruit compote with ginger and/or cinnamon and/or vanilla...then bag up and freeze. Instant crumble/pie filling during the winter or just warm through for compote with custard, add to overnight oats, or defrost and have with cream and meringues.
I give this same one on every quick meal thread, but buy trays of pork loin steaks, chicken breasts or thighs.
On the day you buy them, bag them up with enough for a meal and then dose each bag with different basic marinades like a good squeeze of honey and a spoon of mustard, bbq sauce, or a glug of red wine.... then freeze them. Take out in the morning to defrost, then cook for tea. They will have had plenty of marinade time so are really tasty.