@consumablejoy I am with you there! Total control over my databases!
My database doesn't go so far as to include Sets, but I do record Colour + Main-Colour, which does help in figuring out what goes with what. Plus freeform Tags, which record things like the style of yarn, such as Boucle etc. And of course the usual suspects of thickness, materials, ball size, number of balls, source, cost, and what box it's in.