If you've ever found a mod you've liked except for one little part of it, this mod allows you to selectively remove content. It also works for vanilla / DLC content.
This mod is currently under development and may be buggy. It will be republished to the Steam Workshop once it is complete (as it was unlisted for the first few weeks).
 Some things are not retroactive, like items/gear. Removing them will only prevent new instances from showing up, but existing ones will remain.
 Meats and leathers are special, and can not be so easily removed. Removing these defs only partially removes them, and animals will still use them. A more specialized tool like Optimized Meats would be needed for full removal.
 If removing a drug, the drug policy management UI will only respect removed drug defs for newly created policies, as existing policies are part of the save data.
 If you remove races in such a way that a raid becomes impossible (like no termites, needed for a mechanoid breach raid), you'll get errors and the raid won't happen. Consider removing the raid strategy instead.
 Removing a building's Thing Style only applies for new games, because style information is baked into the save (reforming your ideoligion may also work).
The filter box does a fuzzy search and when you use it, it filters down on the following things: