This one is maybe a bit less common, but if you haven’t deeply experimented with noise, then you really should. From adding punch, to thickness or density, noise – in all its white, pink, brown or other forms – is an incredibly useful tool. While pink noise is the type of noise to use to calibrate audio equipment or set up the global tone of a mix, white noise can bring character and fullness to a dull sound. There’s litteraly a myriad of things you can do with noise !
It’s also an essential tool to create synthetic percussions like snares or hats, sound effects, as well as a wide range of sounds. Moreover, a majority of synths (even free ones) provide a noise generator.