These books, as an alternative to the randomized treasure types and tables found in White Box through at least AD&D 1E, have a guaranteed amount of certain types of objects, and specific names for how many of each kind of object (a Trove is different than a Hoard is different that a Purse, etc.). I'm assuming that this treasure system is codified somewhere other than these two products; if it is, where is it codified and what is it called? If this specific system isn't codified anywhere else, that is also an acceptable answer.
The Lusus Naturae and the Teratic Tome are for the OSR game of weird fantasy Lamentations of the Flame Princess. Caution: That site has an illustration of a person stabbed in the eye as its logo. Folks looking over your shoulder at work might think you're visiting a site about something other than tabletop role-playing games.
This Teratic Tome review indicates that the treasure system, with its assortments, caches, and the like, was introduced in that text, providing a system lacking in Lamentations. This Lusus Naturae review indicates that text continues in the same (ahem) vein, making the Tome the original source for this system.
(I should note that I am a sucker for intuitive organization, and the Tome treasure types are, in increasing large amounts, assortment, cache, coinage, fortune, hoard, loot, lucre, purse, riches, and trove. Those are alphabetical, which is a good idea despite the names being a bit clumsy.)