Vitamin D and Calcium. People say calcium isn't important, or its not as important as Vitamin D and Magnesium. Get magnesium! I can soak my hand or foot in a bowl of water filled with epsom salts for 15 minutes a few times a week and get plenty of magnesium. Also helps me sleep. CVS pharmacy has a huge amount of calcium/vitamin D pills (Get the Citrate, not the Caltrate!) for a low price. I think I got 400 count for less than $15.
Calcium IS important. For bone health, sleep quality, and joint/muscle health, among other things!!!! You can not get enough calcium from just eating your occasional broccoli and kale! I tried that and eventually all my joints really hurt.
Vitamin D and Magnesium help calcium absorption. Calcium is not much without vitamin D and Magnesium. So take all 3!
The rest are easy to get from food.