Over 180 speech therapy worksheets, activities, and flash cards for speech-language pathologists, teachers, and parents. Many of them are free! I created these materials to use with my clients, and I hope you can use them too.
Here is another worksheet addressing the language concept of "not." This is a difficult concept to target, which is why I have made so many materials to work on it! Lots of repetitive practice is needed.
You could also work on this using a set of real life objects (e.g., "Give me everything that is NOT blue. Give me all of the dolls that are NOT boys").