Bard works well: they don't need to use an instrument, but flutes, rattles and drums are there if you want them. You can definitely try to make a performance out of "maniacal cackling".
You could make a pretty good witch out of an Alchemist Artificer. In fact I think that most spellcasters could be successfully flavoured as witchy, with maybe the exception of Paladin (but even so, you might be able to pull it off with the right oath.)
Or ritual jumping over broomsticks, even. What's the difference between performance and ritual with an audience?Bard also works well because music could be replaced with ritual dancing, and the bard's charming and buffing fit a witch class quite well. But in my mind, a witch should also have a strong connection to nature. But perhaps that is where a druid subclass fits in.