Winsor & Newton Winton Oil Color is the brand I’ve used most commonly for the basic colors. Like many painters, you will need a large tub of Liquid white, and a tub of black too. As you develop your mixing skills, you may choose others in large quantities.
Note: You can choose any other brand for the black & white, but Good Ol’ Bob never steered me wrong.
After getting your base set, you will want to consider the colors that move you the most, then branch out to other pallets. I recommend building slowly and using the black & white to stretch a smaller range, before spending on odd hues or colors.
Paints with higher quantities of Cadmium, zinc, or Lead tend to have more vibrant colors, but are much more toxic to use.
Warning: if using these, never sharpen your brush with your mouth or fingers… actually, this is a good rule for all paints.