The Test Kitchen is for odds-n-ends and various experimental skeins. There may only be one skein of each color or there may be a few.
There might be some off-color skeins that got pulled at various times for various reasons that are generally one-of-a-kind (OOAK) and will never ever, ever, ever be seen again.
There might be some bases that were very nice but never made it into the line due to supply issues or some other reason. Needless to say, these will also be OOAK.
This category is like a pot luck kind of thing - very experimental with some very pretty and interesting yarns showing up. Just take note that you won’t be able to get them again.
Also note that some skeins might have a naming sequence like this: Witches Brew #1 Witches Brew #2 and so forth.