That post was too brief , here is more MORE
A thing mostly like an arrow. Hold gently in your hand , say someone's name (the first name their mother gave them) , and it will fly away, faster than a thought and as unstoppable and traceless as a rumour. It will arrive in the heart of the named.
If passed through the pelvis of a creature (regardless if it's alive, dead, skeletal, ash, or fossil) it will quicken and hatch in 2 nights as that creature. An exceptional sculpture can also work, even if it represents nothing that has lived before.
The 7th descendent of this creature will lay The Egg back into the world.
When held breaks anything it hits. After breaking something it begins to vibrate , and after 3 rounds will release a destructive pulse for a kilometre around, pulverizing anything as strong or weaker than what it just broke. It will continue to vibrate and release pulverisation waves until it makes contact with something harder than what it broke to trigger it.
DISTINCT POWER SOURCES FOR ARTIFACTS:
Low Hanging Fruit:
Radically Out of Genre, Anachronistic , Alive and Fleshy and Toothsome, Hyperreal (like at the end of Promethea or the Lego movie mcguffin) , Something physically in the room as the players, Origins in mythology otherwise not used in setting like having Excalibur or The Holy Grail
Jack Kirby style magic technology
Artifact-shaped Nothing , like a hole in space that your eye slides across but sword shaped or something
New Impossible Colours. Grudgingly , "Sunless Sea" was cool with the Neathbow if you want some inspiration
Everytime Artifact Is Used a Star Goes Out
Messages To Players Written On Artifact
Still Living Body Parts From Creator or Prometheus Type
Superdense Material that means artifact ways 100 times more than it should and causes time distortions around
Reshaped Intelligent Beings otherwise not in setting like Draculas , The Middle Class , or Whales
Impossible Machines Of Rutting Cog
Protruding Sex Organ of Extra Spatial being . Appearance gives no doubt of this.
Miniature Cities Frozen at the moment of horrible disasters
Out of Scale objects ; like a urticating hair 2 metres long, or a solar system held in the palm of your hand