This is a thread for Changeling, as well as a other noteworthy mods that don't need a thread of their own. Most of these mods are on 1.10. Changeling is notably also available on 1.12. For the sake of completeness, I'll list all mods with user-facing features, including ones that have their own thread, so they are easier to find.
"To become a thing is to know a thing." -The Dominion, Star Trek DS9
Changeling is a mod that allows you to shapeshift. It is a fork of the excellent Metamorph by McHorse with a focus on fixing survival bugs. It is intended to be lightweight and configurable, and provides an API.
ModTweaker skipped 1.10, so I wrote this mod to modify Thaumcraft aspects. Thaumcraft is a Lovecraft-inspired fantasy magitech mod with many branches of magic, including an elemental system coined "aspects."