If you are looking for a basic choir library with above average Ohhs and Ahhhs this on is pretty good for $39 (I paid $9 to upgrade from the old Micro, and this is much better) It will also work in the free Kontakt player and is NKS compatible.
https://soundiron.com/collections/choirs/products/olympus-micro-choir
 
You get elements of the Venus and Mars women's and mens's choirs. There are some very good Ohs and Ahhs, and a couple of phrases. The interface is decent with layering facilities and legato.