Fresh
Garlic and onions, because I put these in almost everything!
Freezer
Meat and fish from the reduced section of the supermarkets. I buy quite a lot at once, and freeze it all.
Fresh fish, e.g. a whole salmon, which I cut up into reasonably-sized fillets (not the salmon slivers that supermarkets sell), and freeze
Frozen vegetables, like peas and sweetcorn (I don’t use them in huge amounts at once) and carrots (which I eat a lot, so I run out of the fresh ones quite often!)
Cupboards/Pantry
Flour, salt, sugar, gravy granules (until I master making the finest gravy for all kinds of meat), jams, black treacle, golden syrup, dried fruit, stock cubes, coconut milk, tinned tomatoes, tinned salmon and tuna, olive oil, chickpeas, oats, rice, spices, pickled beetroot (I love it!), pickled red cabbage (a rarity around here, so I stock up when I go to visit family in Lancashire), and any other foods from where I grew up. If you go into the supermarkets in areas where there is more multiculturalism, you can pick up huge sacks of rice, flour and lentils, plus enormous bottles of cooking oil, from the World Foods sections. There's also a lot of other interesting things to look at and try from there!
I also stock up on dog food when I go to visit friends in a certain part of the country. It isn't widely available, to the point that I wrote to them and asked if anywhere closer to where I live sold it. My dogs prefer this kind of food, which doesn't give any of them any skin issues, and the variation in the size of pieces is apparently very exciting... so I have to stock up on as many 15kg bags as will fit in a Toyota Aygo without damaging the suspension!