There are a couple of factions out there that enjoy chaos elemental. One such faction would be songhai, since Kaleos can bring in and out with his BloodBorn Spell and Reva can use him as a push away minion with juxta position or just fly it in with Mist Dragon Seal (Kaleos as well). Another Deck that uses him from time to time is Healyonar (AKA zi’ran) since his “High” Health allows it to stay up for some time and you can use it as a healing target. Another faction would be Vanar, since with Hearthsister you can also bring it in and out, but… its way more situational than in the previous things I mentioned ^^;
Even though its a strong minion, its not that good since 3-drops are normally used for their utility, not their overall stats (except silverguard knight)