Even if you strictly follow a nutritious diet, most Americans are lacking in at least a few nutrients because we don't eat the way our ancestors did (you know... the whole animal) and our soil is depleted of the nutrients it once had so the plants and animals we consume are less nutritious.
So take a look at the top 10 list below and decide if you should be eating more of the nutrient containing foods or if you may benefit from supplementing. One thing to keep in mind... supplements by themselves are almost never as bio-available as they are in combination with other components of whole foods. In other words, when able, eat the food rather than taking the supplement.
Supplement
Best Food Source
https://sites.google.com/view/keto-forcera-/