What's the good food for gaining protein?

Fish, poultry, red meat plus whey and creatine and BCAA - does it for me. Combined with good veg and not neglected salt/electrolyte maintenance. Limit processed cr*p.
1. Oily fish - salmon (not farmed)
2. Chicken/turkey - local farm
3. Steak - local farm

Then any combination of locally caught fish particularly fond of hake and sea bream where we are. Am managing to maintain/slightly increase lean muscle mass at my age which is all I really want when combined with weights etc.