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Don't continue reading this post if you don't want to see these items before you discover them in game yourself. This spoiler alert brought to you by one of the awesome dev's, Elric.
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************SPOILER ALERT*************************SPOILER ALERT*************


Let's get a running tally of all the artifacts we've found so far. I've found two so far and I'll list them below. If you've found an artifact, post a screenshot here and I'll add every one to the original post as quick as I can.
*Note, if the artifact comes with a special skill, please provide an image of the skill's tooltip as well!

Some useful information about artifacts we've discovered or the devs have told us:
Combining an Artificers Stone (one can be bought from the Weaver, and another can be found on Zixzax's desk, though you only need one since it's reuseable) with an artifact will destroy the artifact and give you a shard. given that you have high enough crafting ability.
Artifacts can be upgraded to the next tier of awesomeness by dropping them on the ground and using the shards made from other artifacts.This often opens up the unique traits tied to an artifact.
Artifacts were not designed to limit the random loot aspects of the game and will generally not be outright better than a divine item that rolled perfect stats for your character. However, artifacts have many interesting and unique abilities tied to them and are great for enabling hybrid and other interesting builds.

So the easiest way to do it will be to create a dump on imgur and link it here, so here it is!

(Click for images of each Artifact)

• Marauder - One Handed Axe
  
• Zeal - One Handed Dagger -Fumio
  
• Famine - Two Handed Scythe
  
• Patience - One Handed -dark.rei
  
• Hibernaculum - Bow -vashboosle
  
• Lambent Blade - One Handed Sword -vashboosle
  
• Malleus Maleficarum - One Handed Hammer -vashboosle
  
• Sacrifice - Two Handed Sword -vashboosle
  
• The Savage - Two Handed Staff -vashboosle
  
• Vertigo - One Handed Axe -vashboosle
  
• Rod of Command - Wand
  
• Momentum - Crossbow -Grimmeye
  
• Nightmare - Spear -Grimmeye

• The Vault - Heavy Chest Armor
  
• Coruscating Silks - Light Armor -Fumio
  
• Amaranthine Bulwark - Shield
  
• Bounty Hunter - Medium Chest Armor -Grimmeye (Needs Skill Image)
  
• Prismatic Barrier - Shield -vashboosle
  
• Urgency - Medium Chest Armor -vashboosle
  
• Mountain - Heavy Chest Armor -Grimmeye
  
• Antediluvian Carapace - Heavy Chest Armor -Grimmeye (Needs Skill Image)

• Fecundity - Ring
  
• Exaltation - Ring -Fumio
  
• Prophecy - Ring -vashboosle
  
• Ghostflame - Amulet -Grimmeye(Needs Skill Image)
  
• Wendigo - Amulet -Fumio
  
• Seraph - Amulet -Fumio

*Note- Credit for the find will go to the first person to post about the artifact.


Edit_v2: Added spoiler alert. Added list of known Artifacts for a quick glance reference.