You cleanly rip off the corner of a regular un-gimmicked playing card. You now grab the card where the corner once was and are able to control it and move it in all directions.
– Can be done with many ordinary, borrowed objects. Playing cards, business cards, leaves, paper.
– No threads or magnets or see-through plastic. To all appearances, you are literally grabbing air.
– Self-contained gimmick.
– Easy reset.