motif
short musical idea, a salient recurring figure, musical fragment or succession of notes that has some special importance in or is characteristic of a composition
leitmotif
short, constantly recurring musical phrase, associated with a particular person, idea, or situation
head-motif
opening musical idea of a set of movements which serves to unite those movements
Shave and a Haircut
specific 7-note rhythm and melody
Oriental riff
musical riff or phrase
Millennial whoop
musical vocal effect extensively used in 2010s pop music
BACH motif
Musical motif consisting of B flat, A, C, B natural, used by J. S. Bach and other composers