Resistance bands - not listed in exercise databank

I do all of my resistance workouts with bands, and the best thing that you can get for calculating the calorie expenditure would be a heart rate monitor (I use a Polar FT4). All you have to do is enter in your info (weight, age, gender, etc) and hit start. It will track your heart rate and calculate the calories you burn for the whole workout.

All in all, I've found that MFP shows more calories burned for a particular workout than what I actually burn. HRMs are usually more accurate since its tailored to you as a person rather than a general one-size-fits-all calorie converter.

Quick Edit: So you know, HRMs can be used to calculate the calories burned from any exercise, not just bands.