Aspect Tweaker is a CraftTweaker add-on for Minecraft 1.10.2 which allows you to change the aspects of items in Thaumcraft 6. For 1.7 and 1.12, please see ModTweaker.
Currently, only items are supported (and blocks), not ore dictionaries or mobs.
Curseforge's code formatting is broken, so please visit the GitHub source page if you want a quick example showing how to use Aspect Tweaker in a CraftTweaker script.
Aspect Tweaker and my other mods now have a Minecraft Forum page. Please note however that development of Aspect Tweaker is currently on hold.