Primary nutrients such as nitrogen, phosphorus, potassium, sulfur, calcium and magnesium are called macro-nutrients. Keep in mind that just because a plant needs less of a micro-nutrient doesn't mean it is less important to the health of that plant. They are available in higher concentrations and their nutrients are readily available to the plants and inexpensive, making it is very easy to use too much. Natural sources of nutrients, usually derived from living things, are referred to as organic fertilizers. Organics are slowly released to the plants and have low levels of nutrition.
Organics also improve the soil is structure and ability to hold nutrients.
Organic fertilizers tend to be more expensive than inorganic. It is hard to use too much organic fertilizer. There does seem to be a lot to choose from, but they fall into basic groupings that make it easier. Manures and composts are good sources of organic matter and nutrients. Pulverized rock, such as limestone or rock phosphate, are good sources of minerals, but are slow to break down and become useful to the plants.