Apart from his very good other suggestions, I have to disagree with Ichoran, that magic items have to advance or drive a plot to be interesting. A bag of holding is an interesting idea which doesn’t have to be central to the plot.
I agree more with F. Randall Farmer’s ‘Make Items Custom and Personal’.
I say, “Interactive Items Can be Interesting.” In a game I had a ‘snake charm’. This was a little bit of jeweler which from time to time (not controlled by the player) would waken, unravel, slither across my character’s body to a new location and become a different piece of jewelry. For instance it might be a bracelet at one point and later become a necklace, ring, belt, headband, etc.
I’d like to remind you that “the little person finding a magical ring and the GM basing his whole plot” it wasn’t just the cool trick the little person could do, but also that others could sense the ring. It wasn’t just that the ring did x, but, the ring is also interesting because of its other attributes. I bring this up because such a ring tends to interact with the environment and those around them.
- That nice lizard-skin armor means something different when you meet a tribe of lizard-folk.
- That nice bear-pelt cloak seems like a great idea until you get shot in the woods.
- That rare ring from a lost race should attract additional notice from thieves, jewelers, scholars and the like.
- Maybe the item works well, but for political reasons shouldn’t be used in public (or if used shouldn’t leave any witnesses).
The idea is that items themselves can have meaning apart from the use players may normally put them to.
Items that change over time I find interesting. Not just items which grow in power with the character, but items which are situational. A moon sword, tied to the phases of the moon. A Forrestal’s cloak which makes hiding and reduces being hit, but only in the forest. A bloodstone, that you have to feed blood to, in order to recharge it. I once had an item which had a very long delay to it, a sort of time bomb (so the trick was trying to predict when to start it and hope it would affect something when it set off).
Another game I’m working on traps entities into objects to empower them. Certain types of entities react poorly around other types, causing the characters to pick and choose what items they can have about their person.