Where the shape comes from
The Kangxi heading is 无, an old short form of 無 "there is not". 無 itself pictures a dancer holding plumes in both hands — the ancestor of 舞 "to dance" — which was borrowed to write the negative and never returned. Simplified writing kept the short shape, so 无 now does the work everywhere: 无论, and the written counterpart of spoken 没有. Only a handful of characters sit under it, chief among them 既.
汉字 filed under 无
No published character on HSK Guide is filed under this radical yet. 汉字库.