Memory Deluge may have space in some control decks, but I don't see much space for it in the most diverse Jeskai lists, just in control, as the slots are well-defined in Jeskai Opus and Jeskai Creativity. The new rare dual lands will likely see play in decks with two or more colors, mostly in place of some check lands, but not many copies as check lands synergize with shock lands and triomes.
Ultimately, only Izzet Delver is a "new" archetype. But overall, the new set hasn't changed the format. The more cards enter Historic, the less new sets tend to influence, especially when approximately 700 cards from Historic Horizons (comprising cards from Modern Horizons I and II), one of the biggest power creeps in Magic history, came to the digital platform.
Before showing some lists, it is also important to remember that the efforts of the best players in the world are at Standard right now, as the Worlds that will take place on October 8th and the Arena Open on the October 16 will be in that format. As such, Historic will be set aside until probably the Historic Qualifiers at the end of October. The dates are available from the official Wizards website.
For Jeskai, the replacement of 1 Shark Typhoon and Justice Strike with Memory Deluge and Fateful Absence, respectively, were made.
Justice Strike is a nice removal, but the cost of the new card being 1W is relevant, even in a deck with many dual lands and the drawback of creating a clue token is irrelevant.
I believe we can trade a Narset, Parter of Veils or a copy of Teferi, Hero of Dominaria for another Deluge or replace a planeswalker with the fourth Shark Typhoon, but that's the kind of deck who wants 3 or 4 Teferi. Perhaps the second Narset is less relevant, as it fulfills a role similar to the new spell, despite its cost.
Deluge is a card that improves substantially the less Narset has in the format, and at the moment there doesn't seem to be so much to derail Innistrad's new spell.
The famous Izzet Delver has arrived in the format and has been struggling to establish itself due to removals such as Unholy Heat which basically destroys any creature in the format for 1 mana, Pillar of Flames and Lightning Helix, the removal that makes aggressive decks unfeasible.
Honestly, I don't think the deck is going to become something in the format because Delver of the Secrets isn't a really good card, it's a Dragon's Rage Channeler downgrade and nothing else.
Delver has been in Modern since forever and doesn't play because he doesn't have the power level to do so, and it seems that in Historic the same thing can happen. The answers to the creature are similar in both formats, and we don't have the holy trinity of cantrips (unbanned at least), Ponder, Preordain and Brainstorm, the latter having been banned for being too strong for Historic.
At least it's a deck that can benefit a lot from Innistrad's cards like Consider and Smoldering Egg. The Egg is on the sideboard to hold games against aggressive decks and, in just a few turns, turn the game around quickly. Although Unholy Heat kills anything, it takes some time to destroy the Egg, and it doesn't die to Helix or Anger of the Gods, which is relevant against Jeskai.
Another archetype that took full advantage of the improved Opt, Consider, was Izzet Phoenix.
From the spoiler we already said this cantrip will see play in all Magic formats alongside Opt because it does the same function, but better because it can take some Arclight Phoenix, Faithless Looting or some other unwanted card to the graveyard.
To play with 8 cantrips, we removed some copies of removals, but nothing that Unholy Heat can't handle, especially being able to reach delirium quickly with Looting and Channeler. The rest of the deck is the same as before and I don't think I see changes, Deluge is too heavy for the deck and suffers from the same problem as the rest of the deck, loses as soon as Narset, Parter of Veils resolves the other side and is protected by counters and removals.
The new fungus can flip easily, becoming a 3/3 that grows for each creature exiled from your graveyard at the beginning of your upkeep. The deck is designed for either these two creatures to win the game or for Ghoulcaller's Harvest to create an irreversible situation with many zombie tokens on the board.
The entire deck revolves around the new creatures mentioned, having all the other spells and creatures to grind up the deck itself. Egon, God of Death is also an alternate win condition, as a 6/6 for 3 mana can be difficult to deal with.
The sideboard is a bit generic, with graveyard hate (Ashiok), discards and some removals, decreasing the post-side combo and interacting more, as it always happens. A possible addition against aggro decks is Scavenging Ooze, which manages to get out of range of any red removal quickly, gains life, and grows larger than almost any creature.
Other archetypes such as Jund Food/Citadel, Mono Green, Gruul Aggro, Rakdos Arcanist or Rakdos Pyromancer didn't receive relevant additions. Maybe Willow Geist for Mono Green, as it synergizes with Scavenging Ooze, but nothing else.
I don't believe there is any incentive to play Dimir Delver like Pauper, the only archetype for him is Izzet because red removals are as efficient or even more than black, discards can be replaced by cheap counterspells and the deck tends to be very fast thanks to Channeler, which is the best card in the deck.
Maybe we'll see the format change a little more with the other Innistrad set in November.
That's it for today, I hope the lists and explanation about some cards and slots in the decks will help improve them at the future! Any questions or feedback I'm available in the comments below.