I have a lot in mind now. Now I am just agonizing over why these ideas didn't come to me while making the SU. D;
Well one of the ideas is magic that involves photography. So basically, you can take a picture of anything (including magic) and as long as the person who took the picture has the photo he/she can summon it in real life. However, if the person is capturing magic, there is a wait period between 5-10 minutes depending on how powerful the magic he/she is capturing is. See if he/she captured an item, he/she can summon it right away, but with magic he/she will get a blank photo and can't use it until the photo clears up.
I have another one in mind too. (This came while watching the anime Skip Beat. This idea came to me while watching the opening...)