@greg then you've got ceramic caps, which are very small (tiny surface mount parts) and have low parasitics, making them good for high frequency current.
there are two major classes of them: class I and class II.
the class I MLCCs are made from calcium zirconate. they're good at very very high frequencies, and they're extremely stable, but they can't provide a lot of capacitance. they mostly get used for RF stuff.