These spoilers were leaked over the past two days thanks to a really cool fan Timothy Askins on facebook and reddit (and gave permission to share his name).
The original version from 1991 of course used the EU rules, and as such, did NOT include any Artifacts (or "Quest Treasures" as they are known in those rulesets).
SPOILERS (once again)
2 Random Artifacts* - Quest 1
Elixir of Life ("if not already owned by the heroes," repeat from GS, MOTM, etc), 2 Random Artifacts* - Quest 2
Urdyn the Unmaker* - Quest 3
Drakehide Cuirass - Quest 5
2 Random Artifacts* - Quest 9
2 Random Artifacts* - Quest 10
*(may be "unearthed")
"Unearth an Artifact" means you assemble all the Artifact cards excluding the two unique ones from WOM and any that are "already owned" by the Heroes, and draw a random one. Presumably the cards are then held by the heroes, but its unclear if a drawn artifact is used up, it goes back into the deck to be found again potentially (like the Elixir of Life), or here if they are encouraging you to add Artifacts from other expansions
***END spoilers***
Other Artifact Locations:
Game System
Kellar's Keep
Return of the Witch Lord
Elf Quest Pack
Barbarian Quest Pack
Japanese Game System
Mythic Tier quest books
Rise of the Dread Moon
Against the Ogre Horde: this expansion does not feature any artifacts.
First Light
Jungles of Delthrak
