Wrap sandwiches are a quick, portable lunch. Collard leaves make a wonderful Paleo alternative to tortillas for wrap sandwiches. Turn over the leaf and with a sharp knife, remove as much of the rib as possible without cutting through the leaf. I found that it's much easier to do this if I bend the leaf over the edge of the cutting board.
Add sliced meats and cheese (if you are ok with dairy), onion, peppers... or whatever you like. Fold in the ends and roll up. I look for large leaf bunches but if you can't find them, you can set two together: stem-end overlapping stem-end and continue wrapping the same way. You will have a separation you have to pay attention to, but if you overlap enough, your wrap will stay together.
Wrap in plastic.
Another option for filling is cashew cheese or use cashew cheese as a base for mock chicken salad (add onion, celery, sunflower seeds, a bit of apple cider vinegar, some walnuts, if you like).
Dry ingredients work best as fillings since the collard leaf will not absorb any moisture. Meatballs and marinara are not recommended... take my word for it. You may as well try to eat soup with chopsticks.