Grixis decks are all the rage right now in Modern. The Grixis Delver deck is capable of putting on early pressure while having a ton of ways to interact with the opponent. For a while, blue decks in Modern playing Snapcaster Mage were not getting much love, but that is starting to change. The cards here work very well together, and I like being able to run the Young Pyromancer plus Gitaxian Probe package, to be able to immediately get value off Young Pyromancer against other midrange decks. Here is my current list, which is very similar to what has been doing well lately.
Five delve spells is not too many since filling up the graveyard is quite easy, especially with Thought Scour. Serum Visions is a more powerful card than Thought Scour, but Thought Scour is more synergistic so It's hard to say which is better, but both are extremely important. This deck has access to a ton of different sideboard cards, and can be geared towards beating certain matchups. When playing the games, Affinity seemed like it could be a difficult matchup, but in practice it wasn't.
This deck can overload creature-based decks with removal very easily. Shattestorm was the nail in the coffin for Affinity as a very mediocre draw including Shatterstorm was certainly enough to get the job done. I like having access to lots of different removal spells because it makes any one card more difficult to play around. Spell Snare here was lights out as the two-mana plays are a lot of the most important cards from the Affinity deck.
When we squared off against the Sultai Control deck it became evident why Grixis Delver doesn't need Ancestral Vision. The Painful Truths in the sideboard can provide card draw and we were able to fight through multiple resolved Ancestral Vision. Grixis Delver is great at having lots to do early in the game while still having more cards than the opponent later on, which is the perfect recipe for success. During these matches we dodged some of the bad matchups like Dredge, but even there you can add a bunch of sideboard hate to improve the matchup.
The matchup against Red-White Prison ("Sun and Moon") was about being able to play around cards that are known in that deck. Countering a Chalice of the Void was enough in game one to completely stop what the opponent was doing. Being able to take out removal spells for countermagic and card draw is great. This was my first time playing this particular matchup, but Grixis Delver felt very favored, as long as the Red-White Prison can't stick a perfectly timed Blood Moon.
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