An ostinato is an element of a musical piece that keeps the time, not to be confused with "Riff", which is the term for repeating something in music, though it is commonly thought of as only applying to guitars.

In the vein of players like Terry Bozzio, Akira Jimbo also stands out when it comes to playing melodies over rhythms. Akira Jimbo uses electronic drum pads set to orchestral sounds at various pitches to create a much broader range of notes available for his melodies. Other drummers do this as well, but you'd have to see Akira Jimbo to believe it.

In terms of drumming, and in terms of "rock" music in general, the hi-hat often provides the ostinato, though anything can. More people should think outside the box on this one. Sometimes there is no ostinato exactly, for example, classical and opera singers are traditionally required to sing without giving any hint of ostinato, to keep their own time, perfectly, in their head, without swaying their body rhythmically, tapping their foot or making any rhythmic/timekeeping sounds.