odds and ends vs assortment

odds and ends and assortment both are nouns.

Word	Noun	Adjective	Verb	Adverb
odds and ends	Yes	No	No	No
assortment	Yes	No	No	No

As nouns, assortment is a hypernym of odds and ends; that is, assortment is a word with a broader meaning than odds and ends:

Other hypernyms of odds and ends include miscellanea, miscellany, mixed bag, mixture, motley, potpourri, salmagundi, smorgasbord, variety.

odds and ends (noun)	assortment (noun)
a motley assortment of things	the act of distributing things into classes or categories of the same type
	a collection containing a variety of sorts of things