If you've played BO1 on Arena you've probably definitely seen this deck, but it's making some waves in BO3 as well.
It's pretty simple, mull until you get a hand with either of the discover cards, lands/ramp or filtering cards to find them. An ideal hand has one of the discard-for-a-treasure sorceries, 3 lands and an Appraiser to go off turn 3, but with several of the treasure ramp cards you can also go into a turn 4 Dinosaur. Either Consign or Bedeck serves as our interaction without getting in the way of Discover.
Once you've started the discover chain, with Appraiser you'll hit either a clone (Glasspool is preferred but you can use Mirror Image if you're light on wildcards) or Eldritch Evolution. Evolution gets us to our Carnosaur, which starts the chain again but we can hit Appraiser as well. Continue until you find the last Eldritch Evolution and grab a Doomskar Titan to give everything you control +1/+0 and Haste.
Between this and Quintorious combo I feel like there's a strong chance of something getting hit on the list. Given that it's all based around Discover, could we see an errata similar to Companion? I feel like it's unlikely, given that they could have just put "if this card was cast from your hand" and not had this issue
Decks that only aim to combo out and are completely indifferent to anything you are doing are a bane on the game and the reason I would exclusively play limited if it were an option.
I wish wotc would aggressively ban the key pieces of these decks that let them basically cast half their deck after resolving a single 3 mana spell.
Wotc can do this, sure... so long as they restrict it to BO1. In BO3, decks needing to run a couple pieces of hate/interaction in the sideboard to deal with a linear combo is good for the health if the game, if anything. (If that's still not enough, then sure, ban it globally. But BO1 and BO3 are fundementally different games.)