Dexter on his own in fish town (core, IC, and EotE)

The final deck at the end of the Innsmouth campaing. This is what it looked like when going into the final scenario (yes, it says 'scenario 5 complete' but you don't get to spend exp after every scenario in Innsmouth). This is not an optimal build in any way but what a deck can look like after failing forward through a campaing. And despite some failures along the way it did fine in the final scenario.

Main focus

In true solo you need to both handle enemies and collect clues. The workhorses for these two tasks are Armageddon and Divination. You also sometimes need to move a lot. Scout Ahead is for this.

The rest of the cards exist to boost these two workhorse spells, to tutor them, or as supplements in cases where you don't have the workhorses with you.

Boosting the workhorses...

Both Armageddon and Divination have you test will power. Holy Rosary, Blood Pact, and Prophetic are there to boost will power.

The Arcane Initiate tutors the two main spells.

... or plan B

Should you find yourself without the two main spells, you have Sword Cane, Blinding Light, and Mind Wipe to avoid the nasty monsters. Notice that the first two are also will power tests and therefore get boosts from the same cards that boost the spells. Drawn to the Flame lets you find clues when you needed it but don't have Divination.

Ríastrad packs a heavy punch when you don't have Armageddon, and can be further boosted with Blood Pact.

Curses

In addition to its punch, Ríastrad adds curses to the chaos bag, which is important for getting the full effect from Armageddon. Faustian Bargain also adds curses (and five resources) and so does Promise of Power and Priest of Two Faiths. So there are lots of ways to get cursus, and Favor of the Moon helps you manage them. There are no cards mitigating curses. Instead, there is emphasis on over succeeding. All cards that boost will power add to this. The blessings from Priest of two Faits also help. Promise of Power also lets you over succeed but it also is useful for boosing stats other than will power when the encounter deck throws something really ugly at you. It is actually the only card here to manage bad encounter draws.

And the rest

There is no healing but there is soak from Arcane Initiate, Priest of two Faiths and Holy Rosary. This does not help the trauma from In the Thick of It, but it was necessary to take In the Thick of It to have Divination(1) in the first scenario of the campaign.

The deck is heavy on assets (there are 18 plus his signature cards) to exploit Dexter's special ability. The special ability means that you can get doom on Arcane Initiate and on Blood Pact out of play when needed.

A great synergy is that, while Prophetic is already good to have to boost the two main spells and Arcane Initiate tutors them, there are several cards that are also spells without taking up an arcane slot: Blood Pact, Ríastrad, and Blinding Light.

Finally, economy: most cards here are quite cheap and Faustian Bargain and Prophetic help you pay for the two main spells.