collectible vs oddity

collectible and oddity both are nouns.

Word	Noun	Adjective	Verb	Adverb
collectible	Yes	Yes	No	No
oddity	Yes	No	No	No

As nouns, oddity is a hypernym of collectible; that is, oddity is a word with a broader meaning than collectible:

collectible: things considered to be worth collecting (not necessarily valuable or antique)
oddity: something unusual -- perhaps worthy of collecting

Other hypernyms of collectible include curio, curiosity, oddment, peculiarity, rarity.

collectible (noun)	oddity (noun)
things considered to be worth collecting (not necessarily valuable or antique)	something unusual -- perhaps worthy of collecting
	a strange attitude or habit
	eccentricity that is not easily explained

collectible (adjective)	oddity (adjective)
subject to or requiring payment especially as specified