I do both carb and calorie monitoring.

If Im maxed out on carbs for the day and still need calories, these are the things I eat:

cheese (cracker barrel cheese sticks are like 120cals per stick with no carbs)
baked chicken
coleslaw (mayonnaise- high fat, cabbage- lo carb)
egg white omelettes filled with cheese and low-carbohydrate veggies)
lots of heavy cream in my tea of coffee (how carb, high calorie)


My main thing though is cheese- if I'm having one of those days where my appetite is very low, I'll just eat a cheese stick, or cream cheese on cucumber slices to get my calories up.

Hope this helps.