Question: Can I take Yok3d and another pre-workout powder, together? Or will this harm my body?
Answer: Taking Yok3d plus another pre-workout supplement should not cause any problems.
The only negative side effects that could realistically occur would be a headache and some nausea. This would only happen, though, if you were consume too much total caffeine or other stimulant. The same thing would happen if you had too much of just the Yok3d supplement, itself.
In other words, it's the cumulative quantities of the stimulant ingredients (e.g. caffeine) from both supplements that would matter; not the actual mixing of different pre-workout supplements.
So, I would go for it, but start with smaller servings of each supplement and taper up from there. That way, you'll avoid the possibility of a headache and stomach ache from too caffeine or other stimulants. Also, you'll be able to zero-in on your optimal dosages for each supplement.
Please note, however, that I do not know your personal medical history; and furthermore, I'm not a qualified medical professional. For matters such as these, it's always a smart practice to consult a qualified physician. (See full disclaimer).