I played UR Delver pre-Treasure Cruise, Top 8'ing both PTQs I played it in (with a finals loss). It had everything I was looking for in a Modern deck: consistency, a proactive game plan, a diverse suite of versatile answers, ways to grind out the late game (Snapcaster Mage + Electrolyze), and some good matchups (particularly Pod and Affinity).

It had its problems, specifically against UWR and the GBx decks. Jund in particular was good at either tempo'ing you out with multiple Tarmogoyfs (one 'Goyf was manageable) or out-grinding you with Liliana of the Veil. Post-board, the Pyromancers did less work because they had cards like Anger of the Gods, which were intended for Pod.

To combat both of these decks, I started maindecking Blood Moon (incredible, game-winning, unexpected) and Batterskull. Batterskull seems strange in a 19-land deck, but when you're cantripping this hard you'll hit land drops whether you want to or not, and if you can't cast Batterskull then you're probably sitting on the perfect 2-3 lands and not missing the loss of a single card.

I expect the post-banning metagame to be heavy on Junk, Affinity, and Twin. Since a pile of Forked Bolts, Electrolyzes, and Snapcasters has a naturally good time against Affinity, it makes sense to focus on the other matchups.

Twin is an easy one, just make sure you're not a complete dog in game one, play tight, and board in a few Combusts for the g2/g3 blowout.

Junk is a tougher nut to crack. UR's biggest problem against the GBx decks pre-Cruise was that Tarmogoyf is too large to handle. Now, they get Siege Rhino, compounding the problem, and Tasigur has been showing up in various quantities.

In the recent GP, I saw a number of Delver decks sideboarding Flashfreeze to beat Siege Rhino, and the more that I think about it the more I like the idea of maindecking the card. You're going to need to beat a Siege Rhino in the main deck, and it's pretty solid against Twin, Scapeshift, and Electrolyze decks. While it's not ideal against Tron, the only matchups it's really dead against are Affinity and Merfolk.

Siege Rhino's color-centric casting cost is a great reason go back to maindeck Blood Moon.

UR Delver

You could get more aggressive with Monastery Swiftspear, but I think it's more likely to get stonewalled by the new Junk archetypes. One of the great things about Swiftspear was that you could draw into it off of Treasure Cruise and attack through Tarmogoyfs on that very same turn. Without Cruise, Swiftspear will still get some busted draws from chaining cantrips together, but unlike Young Pyromancer the spells need to be on your turn to matter, which doesn't synergize with countermagic.

Junk

Out

In

For the most part, you're maindecked for this matchup, although you do want to board in some 2-for-1s that are good against Tarmogoyf. While Abrupt Decay hits Threads and Path to Exile hits Sower, they're both great against Liliana. Ideally, you'll overload their removal between all the Delvers and Pyromancers and Blood Moons.

Burn

Out

In

The addition of hard counters to the main deck helps things, since Remand isn't ideal and at a certain point Spell Pierce falls off.

Affinity

Out

In

Hard to lose a full match.

Twin

Out

In

Threads of Disloyalty is mostly here as a value-tastic way of answering Spellskite, and Twin can have these random grindy games where stealing a Snapcaster Mage or a Grim Lavamancer breaks parity.

Tron

Out

In

It's not the most exciting sideboard swap, but we do have Blood Moons maindeck.

Boggles

Just cry a little.

But seriously, if you're worried about this matchup then the best answers are Engineered Explosives and Hibernation. Hibernation could double as a super-Vapor Snag against Junk, but I worry about having too many Unsummons and too few real answers in that matchup, which is why I currently have the Threads and Sowers.

Merfolk

Out

In

Combust is a sicko answer to Kira, Great Glass-Spinner.

Scapeshift

Out

In

Snag seems better than Dismember because it can save your creatures, but I like being able to one-shot an Obstinate Baloth.

Once again, maindeck Blood Moons are very strong.

Storm

Out

In

Always leave up the mana to answer Electromancer, as they'll often save it for the combo turn.

Zoo

Out

In

Blood Moon is actually excellent against Zoo, and between all the Wild Nacatls, Kird Apes, and Loam Lions it can have an immediate impact on the board.

UWR Control

Out

In

While Flashfreeze can counter an Electrolyze or Lightning Helix, Dispel does it all for a bit cheaper while also hitting Cryptic Command. It's nice that the Flashfreezes aren't dead, but they don't stay in.