Stealth Dice are spies and information gatherers. They have the basic ability to sense the proximity of other Dice, making them very useful as one of the first Dice to catch.
As a Stealth Dice, Stealth had an excellent sense of smell and as a cat, extremely good eyesight, even in bright light. Off in the distance, she could see something unnatural moving, long and fluttering. That had to be it. She couldn't smell it, but she could see it and also sensed that it was a Dice. The skills of the Stealth Dice. (AD, Day 2, strip 4)
"I'm also a Stealth Dice. I'm a spy. I listen. I pay attention. I learn." (AD, Day 1, strip 43)
They have the ability to speak without being heard, (AD, Day 4, strip 21) and some have developed the ability to the point where they can walk in others' minds, but don't have the ability to read them.
At higher levels they have the ability to detect lies.
At highest levels they can alter their appearance for camouflage.