A few weeks ago we got some unofficial spoilers on Theros Beyond Death. Normally, we avoid digging too much into anything that is unsubstantiated given that we have seen plenty of fake spoilers. However, the cards shown appear to be more than just an image but the actual picture of the card which gives some credibility to their spoiling. It also helps that they aren't outrageous and seem viable.

I bring all this up only because we have seen multiple times that cards that appear to be plants for upcoming sets or that work very well with a new set/blocks mechanics often spike in price. The mechanics we see on the spoiled cards are;

Devotion

For those who didn't play during the last Theros Standard, the devotion mechanic proved extremely powerful. So powerful, in fact, that there was little reason to play more than one color for a significant amount of time in Standard. Admittedly, a fair amount of that power came from the fact that each color had access to Nykthos, Shrine to Nyx which helped generate massive amounts of mana for any color. This mechanic was also the reason that a card like Nightveil Specter went from bulk to big money.

It is because of this card specifically that I'm writing this article, as I was lucky enough to have upwards of 20+ copies when the spoilers started rolling in, thanks in large part to my actively acquiring bulk rares at the time. The beauty of this mechanic is that many of the cards that directly benefit it are set/block specific; it can be assisted by cards from any set or block which allows for a lot of opportunity for speculative gains. A word of caution though, because this mechanic cares solely about the mana costs of cards it means there are plenty of options in each color. That wide openness means that there will be a lot of cards that could fit into a devotion deck, but likely far fewer that should. So cards that I do find as interesting speculative options are;

The fact that these are mythic rares means there is a higher potential price ceiling and the fact that they are from a core set means there are likely fewer in supply thanks to the general lack of desire to draft core sets by most players. They all add three to their given devotion color and all have enters the battlefield abilities and leaves the battlefield abilities. There are currently only four cards in the set whose market price exceeds $9 so the RoI of a pack is extremely low; which means that we aren't likely to see a lot of people cracking packs. These cards are powerful enough that they could see play in non-devotion strategies, though arguably their mana cost then becomes a bane rather than a boon.

Throne of Eldraine Cards

There are currently two Throne of Eldraine cards I would consider as decent speculation targets for the devotion mechanic.

Murderous Rider is already a very playable card without the devotion mechanic. It is very similar to Hero's Downfall way back from Mono Black Devotion's dominance in the first Theros block, except it also has a lifelinking body attached as well. Rider is seeing significant play in various Pioneer builds and should we see a mono-black devotion develop in Standard this is definitely a four-of card. This card has remained relatively stable the past few weeks and there is likely to be a lot of ToE opened thanks to having so many high dollar cards so supply will likely continue to flood into the market.

Brazen Borrower is also a card we are already seeing play in multiple formats and similar to Murderous Rider both halves are good spells on their own. Unfortunately, the current buy-in price on this card is already above $16, which is pretty steep for a Standard-legal mythic. We know that the price ceiling on standard mythic rares these days is around $50 and that requires utter dominance of the card. However, given the current demand is propping the price of this one up there is less risk of loss should Mono Blue devotion not pan out. If it does, then this could easily be a $30 card.

Leylines

The leyline cycle is an interesting speculation target because it falls between two different known Theros Beyond Death archetypes; Devotion and Constellation. We have seen how powerful the Core Set 2020 leylines are in devotion builds courtesy of the mono-green devotion deck that got banned into oblivion in Pioneer. The ability to have two+ free devotion on turn 0 is huge with the devotion mechanic. One important thing to keep in mind though is obviously that you need a payoff card or cards to justify maindecking some of these leylines.

We haven't seen anything like Nykthos, Shrine to Nyx spoiled yet, so I don't know if I'd go too deep on any specific leyline, however, it's important to keep in mind that 3 of them (Leyline of the Void, Leyline of Anticipation, and Leyline of Sanctity) have been worth far more than their current price so even if no standard deck were to develop your risk on them isn't all that high. I'm not a big fan of Leyline of Combustion as it's ability seems the least powerful in our current environment, however, should we get some form of aggro red devotion deck it would likely be a 4 of.

Constellation

Currently, we actually don't have a ton of rare or mythic enchantments in standard at the moment. I have already covered the Leyline cycle which aren't actually all that good in Constellation builds; the ability triggers on enchantments entering the battlefield, so you don't gain anything from them starting the game in play, but at least they would trigger if you drew them outside of your opening hand. The only card that seems like a plant for Theros Beyond Death in the current Standard is Starfield Mystic, which might see a price jump should a strong white constellation enchantment be spoiled, but it currently seems underpowered.

Escape

The Escape mechanic is new to this set and it doesn't seem to play all that well with any existing Standard-legal cards so I don't see any major potential speculation targets due to this mechanic.