My main sources of protein are:
Egg whites
Greek yogurt
Protein powder
Chicken breast
Cottage cheese
Any way that you can combine those things is going to stack protein really hard. I usually go for about 40-50g per meal
For example:
A half cup of oats in the morning is 5-10g of protein. Mix that with half a cup of Greek yogurt for another 10g.
Egg whites are low calorie and high protein. You can scramble those up with some low fat mozzarella (tillamook has good protein) and add salsa and Greek yogurt (just pretend it's sour cream). Throw an avocado in there. Throw some turkey breast slices in there (high sodium but also high protein).
Those are high as hell delicious protein meals
Oikos makes a protein pro yogurt that is 20g of protein per cup and is sugar free
Cottage cheese is a high protein additive that can be snuck into a lot of things. On its own, it's delicious with freak in my opinion, but you can whip it into your eggs, and it's delicious. Try to think of other ways you can incorporate it. Salads, veggies dip with hummus maybe, etc
Protein powder is great and is usually 25-30g a serving. Mix it in with yogurt, and that's like a 45g serving of protein
Beans and lentils and such are also a great source of protein that you can add in. Maybe in your egg white bowl in the morning.
Finally, meats are just a great way to get protein.
A chicken breast has 43g of protein. You eat one for lunch with a salad with chick peas and cottage cheese? Huge protein
You eat one for dinner with some broccoli and rice and beans? Big protein
Fish, lean beef, SHRIMP are all low calorie and high protein
For lunch today, I had 4 turkey breast slices. Each of them had like an ounce of cottage cheese on it, half of a hardboiled egg, some spring mix, and some cherry tomatoes.