Excluding Protein, Fat, and Carbs, what else should I track?

I think fiber is important.

I track sodium and fibre but really the choice is very individual. There is no right or wrong with this one.

Fiber. And whatever else you want. I do potassium but that is kind of useless because the data entries mostly don't account for it.

I track whatever I think I may not be eating enough of. I do find if I eat enough vitamin A and C foods (veggies), I automatically get more fiber than I needs, so I've never bothered to track fiber. I sometimes change the settings to check one nutrient over another or just go to "reports" to check how I'm doing. The potassium entries are a problem as mentioned above, but you *can* find ones that include potassium if you are determined, usually the usda entries. If you eat lots of fruits and veggies, legumes, potatoes, you will notice they are the foods highest in potassium. I track it just because it is so important and so lacking in the typical American diet, plus hypertension is in my family history, and I want to avoid it.

I track fiber, calcium, and iron.