Is there knock out drugs that are leagle?

Yes, there are legal drugs that can have sedative or "knockout" effects, often prescribed for medical purposes. For example, certain benzodiazepines and anesthetics are used in clinical settings to induce sedation or sleep. However, using these substances outside of prescribed medical contexts, or for the purpose of incapacitating someone without consent, is illegal and unethical. Always consult a healthcare professional for appropriate use of any medication.