I'm working on a set of supernatural creatures, their powers and their culture/social structure.
One of these races have the power to make gifts appear out of thin air. They can be anything from spell book to smartphone and their one and only recipient must be present when they are created. These gifts are either something the recipient wants, needs, or would love to own even if they don't know it yet.
This is for now their only power. They are otherwise humans.
The main problem is that beings able to create anything from atomic bombs to boxes full of diamonds would be way too powerful. They risk becoming basically gods or being kidnapped by other creatures and milked for useful and expensive goods.
Another problem is that they may be too "santa-like" to be interesting as characters. A creature that only appears to give protagonists exactly what they need would turn the story into a stream of "Deus ex machina" moments.
My goal is to have them being powerful enough so they can have a good social rank in the underworld (which is basically a network of magical mafias), but not become godlike figures. They also need to face some sort of human struggles (emotional/familial/economical) to keep them from becoming too artificial.
I thought of three different ways to restrain their power, but none of them is satisfying:
Feelings : They can only give awesome gifts to the people they like, and useless junk to the rest. Problem: thanks to the Stockholm syndrome, it wouldn't prevent the kidnappings.
Dates : Their power only works on birthdays/Christmas/Hanukkah/Weddings/Eid/etc., but it would make them too predictable and boring. Plus, how to choose which holidays to use?
Sanity : Easy but lazy rule. They could be all insane and thus easy to fit into any story, since their behavior wouldn't need to be consistent.
What do you think of these 3 possible rules?
How could I keep them fun without turning them into insane trolls or "Deus ex machina" characters?
You can use any set of rules you want, or even give them additional (related) powers and personality traits.
The gift generated are literal gifts, they appear inside boxes, packed in colorful paper. When a gift appears, no one know what's inside, not even the creature itself.
I'm looking for the simplest way to limit these creatures power, without altering them too much.