Many players would still be playing if there was a continuation to this system: one where you unlock appearances through activities and achievements, not just item drop / RNG. Pursuing artifact appearances
Hidden Artifact Weapon Appearances and Effects - Wowhead
UPDATES IN COMMENTS!) Hidden Artifact Appearances for Shamans (Hidden Potential) | WoW Guide - YouTube
Here's what's happening to your Artifacts in Battle for Azeroth
Hidden Artifact Weapon Appearances and Effects - Wowhead
Hidden Frost Death Knight Artifact Appearance Now Available on Live Servers - News - Icy Veins