Cottage Cheese is always high protein/low fat (98kcal per 100g), the brand shouldn‘t matter much. Yoghurt comes with either 0.3%, 1.5%, 3.5% fat (Fett). Greek yoghurt is always high fat yoghurt (10%) with higher amounts of fat and protein in it, I don‘t think we have a low fat option for it, but I‘m not completely sure. Quark is a somewhat denser yoghurt with much higher amounts of protein that does come with 0.3% (Magerquark), 10% or 20% of fat. Lower fat cream (Sahne) for cooking is called „Kochsahne“, it contains around 15% percent fat instead of the 30% in the somewhat default cream which is also meant for baking (Schlagsahne). For all this stuff the brand shouldn‘t matter regarding the nutritional values (Nährwerte), just look for the percentage of fat (Fett) in the front or in the back on the table for the nutritional values (it‘s always the amount for 100g).

If you try Magerquark (thats what the body builders here eat), I would really recommend to mix it with (plant based) milk and maybe a sweetener or it will taste horrible (very sour and the consistency is too dense). 10% Quark tastes much much better and in most of the stuff I prefer the middle amount of fat (or even the 3.5% in Joghurt, one 150g portion still has only 100kcal), because I think it‘s stupid to pay for tasteless water that never satisfies or enhances a dish in reasonable amounts. Magerquark has at least very high amounts of protein so it has it‘s value, it‘s just not a great taste if not pimped a bit.

As a cheese for cooking and salads I really recommend Feta (soft, salty, greek cheese), it does much to enhance a dish even in small amounts and has less calories than gouda and all the other harder cheese varieties

Oh and if you drink cow milk always buy one of the cooled ones, H-Milch tastes horrible and is only meant as a backup for coffee or baking.