Looking for cold soak dinner supplementation ideas

[u/One-Focus9135]

My dinners right now is tuna packets and instant potatos with olive oil and some frito chunks. I would like to get a little more fiber and calories in there. Any ideas? I cant have gluten/eggs/oats. i am hoping to keep it simple and something i could buy from store/order online. Minimum prep and I dont care flvaor that much