With today's technology, you could control an entire army with a simple thought.
A realistic superpower that could be implemented is mind control over someone else’s body. This has been shown to work, on a more comical scale, with the Human-Human Interface where one person’s muscles send signals to another persons muscles by the use of transcutaneous electrical nerve stimulation (TENS).
Check out “The White Rabbit Project” video in the link for a good laugh. (Sorry I couldn’t directly link the video to this pub)
This is done by attaching small electrodes at specific parts to a person’s arm to activate the appropriate muscles. It’s reasonable that these electrodes could be sewn into the fabric of a shirt, or even an entire body suit, where all the electrodes would line up perfectly with the muscles. This would remove all the pesky wires seen in the video. The entire suit would act as a TENS unit removing any freewill from the user. It’s reasonable to think that you could map all of the TENS movements to voice activation. For example, a person could say, “Move your right arm up” and all of the necessary TENS would activate to move the persons arm. This seems much more of a villain superpower than a hero superpower as seen in the video.
It’s also interesting to think that there is no limit to the distance that this device could reach. Potentially you could control someone across the world as long as the TENS suit was hooked up to some kind of cellular signal. If multiple people are wearing the suits then you could also have an entire army of slaves with no control over their bodies. The ethics of such a superpower are obviously questionable.