Innistrad: Crimson Vow, arriving on November 19th, is Magic: The Gathering's next Standard set. Crimson Vow revolves around a Vampire wedding, and we can expect it to highlight new Vampire cards, similar to how Innistrad Midnight Hunt prominently features Werewolves. 

During Midnight Hunt's spoiler season, older Werewolf cards spiked in price. My article, Which Cards Spiked Because of Midnight Hunt, suggests organic demand drove multiple price spikes as players purchased Werewolf cards for Commander decks. We can envision that Crimson Vow will send the price of some Vampire cards upward as players aim to build decks with new and existing cards. Edgar Markov, the most played Vampire commander on EDHREC, saw his average market price climb since August. 

Edgar Markov is not the only Vampire Commander that sees play. The next-most popular Vampire commanders are Vito, Thorn of the Dusk Rose, Elenda, the Dusk Rose, and Olivia Voldaren. One or more Vampire characters from Innistrad's rich storyline will likely return as a Legendary creature in Crimson Vow.
One common theme among the most played Vampire commanders is that they are all black in their casting cost. Out of 286 Vampires in MTG, 65% are mono-black, and 81% have black as one of their colors. 

I believe it is safe to assume if any Vampire cards spike in price due to Crimson Vow (and dodge reprints), they will likely be black. Let's take a look at a handful of black Vampires that could see heightened demand and price spikes come November.

#1 Vampire of the Dire Moon

Vampire of the Dire Moon is a 1/1 Vampire with lifelink and deathtouch for one mana. The number of keywords on Vampire of the Dire Moon, combined with its inexpensive casting cost, make it appealing as a curve filler for Vampire decks. Vampire of the Dire Moon can trade up with another creature on the battlefield, and increasing its power and toughness can turn it into a sinister force. 

Fortunately for Vampire of the Dire Moon, there are plenty of ways Vampires can receive +1/+1 counters. Edgar Markov, Drana, Liberator of Malakir, and Cordial Vampire make it easy to add counters on fellow Vampires. Vampire of the Dire Moon synergizes well with multiple Vampire commanders, which may be one reason why it maintains an average market price of almost $2. By the time Crimson Vow is released, Vampire of the Dire Moon could be approaching a market price of $4.

#2 Cordial Vampire

The potent ability of Cordial Vampire is hard to ignore. Whenever any creature, including Cordial Vampire, dies, you get to put a +1/+1 counter on each Vampire under your control. Sacrificing a 1/1 Vampire creature token created by Edgar Markov's Eminence ability is a simple way to pump the team. Killing one of your opponent's creatures in combat or with a removal spell will also trigger Cordial Vampire's ability. 

Interestingly, Cordial Vampire's average market price rose within the last two months from $2 to $5. A buyout occurred on August 19th, with an average of 8.2 copies purchased per buyer. With 138 copies available on TCGplayer as of October 4th, it will not take much additional demand to push Cordial Vampire's price to new highs. There is still room for Cordial Vampire's market price to run higher. 

#3 Blood Artist

Blood Artist is a top 10 black Commander staple with over 40,000 deck inclusions on EDHREC. Whenever Blood Artist or another creature dies, a target player loses one life, and you gain one life. It pairs well with Cordial Vampire, as both abilities trigger when a creature dies — including their own. 
The playability of Blood Artist spans beyond Vampire Commander decks, which helps it maintain an average market price of around $6. Even with reprints in Jumpstart and Mystery Booster, Blood Artist still holds a solid price point. Any spark of demand for Vampires with powerful abilities may move Blood Artist's price closer to $10. 

#4 Captivating Vampire

Don't let that charming face fool you; this is one powerful Vampire. Captivating Vampire provides +1/+1 to other Vampires on your side of the battlefield, and can gain control of a target creature with some help from a few friends. In a recent article, 10 Black Cards You Should Be Playing, I mentioned that mono-black cards with the capability to steal an opponent's creature are rare. 
Paying three mana for Captivating Vampire is a real bargain at its current market price near $11. I can see Captivating Vampire's market price easily double as players scramble to pick up the most appealing Vampires for Commander.

#5 Bloodline Keeper

Bloodline Keeper is a double-sided Vampire that can increase the power and toughness of other Vampires by +2/+2. Bloodline Keeper can also produce a 2/2 black Vampire creature token with flying, simply by tapping it. Even if your board is empty, Bloodline Keeper can help rebuild an army of Vampires to overwhelm opponents. 
Wizards of the Coast's Good Morning Magic! video series highlights the difficulty of double-faced card printing in Commander preconstructed decks. As such, the only feasible place for Bloodline Keeper to return as a reprint is in the main set of Crimson Vow. If Bloodline Keeper does not show up, I expect its average market price to skyrocket from $14 to $20.  

#6 Drana, Liberator of Malakir

Initially printed in Battle for Zendikar, Drana, Liberator of Malakir is a powerful Legendary Vampire Ally with multiple abilities. Whenever Drana deals combat damage to an opponent, you get to put +1/+1 counters on each attacking creature you control. Since Drana possesses first strike, any attacking creatures without first strike may get buffed before resolving all combat damage.
Drana, Liberator of Malakir is a familiar presence in the 99 of Edgar Markov, Felisa, Fang of Silverquill, and Olivia Voldaren. The evasiveness and +1/+1 counter ability make it a great fit in aggressive Vampire decks. With a market price of around $4, Drana, Liberator of Malakir is ripe for a price increase if demand jumps for effective Vampire cards. I anticipate Drana's market price to potentially rise 100% to 200% depending on Crimson Vow's card inclusions.

#7 Patron of the Vein

Patron of the Vein is an exciting top-end for Vampire Commander decks. Upon entering the battlefield, Patron of the Vein typically destroys a target creature an opponent controls, puts a +1/+1 counter on each Vampire you control, and stays around as a 4/4 flyer. As the game progresses, Patron of the Vein continues adding +1/+1 counters to your Vampires each time another creature dies under an opponent's control.
Currently, Patron of the Vein sees play in Commander decks featuring the most prominent Vampire commanders. With low supply availability on TCGplayer and an average market price of $11, Patron of the Vein could be an easy buyout target. If this is a card you might be considering for a future Vampire deck, I recommend not wait much longer to secure a copy.  
With an upcoming Vampire-centric set, it is more likely vampire cards will increase rather than decrease in value. The cards above are what I believe to be top contenders for potential price spikes due to Crimson Vow. If you have any appealing Vampire cards on a Commander deck wish list, consider picking them up before Crimson Vow spoiler season is fully underway.