In a fantasy world, everyone uses candles. Whether for lighting, magical rituals, or even decoration, they're everywhere. Surely, there can be few better ways to make something powerful look mundane. Even better, candles can be clearly defined as on or off, and so have no need to be programmed with command words or switches. Everyone knows how to light a candle.
A magical candle could be helpful for anyone, and could prove relatively simple to manufacture, compared to other sorts of magic.
A random generator can be found here.