Scarlet Witch - Ah, it is empty movement!

Designed for explosive first turns, and limited to my physical collection (though I've proxied some alternates, listed at the bottom).

First turn:

• Mulligan away everything that isn't a resource generator, card draw (The Sorcerer Supreme counts), Chaos Magic, a double, or Scarlet Witch's Crest.
• "Wanda mulligan" away two more cards with Superpowered Siblings.
• If you're holding Agatha Harkness, play her immediately and activate her for net -1 resources. Then/otherwise flip up.
• Play One Way or Another - you'll have it most of the time, that's why there's three copies in the list - fish out the least scary enemy side-scheme, and don't clear it unless you can do so trivially. You can probably handle an acceleration token for the first few turns (...you'll have to later on in the game in any case!).
• "Spiritual Meditation mulligan" away any more cards that aren't in the above categories (including additional copies of OWoA unless you like living dangerously).
• Play as many supports and upgrades as possible - you'll usually play at least 9 to 12 effective resources' worth out (more if you're holding Chaos Magic plus Avengers Mansion), and if you have to spend the last couple of points on a Magic Shield or Hex Bolt, that's not exactly a terrible thing.

After that, this list provides the bare basic things Wanda wants:

• Card draw

• Resource generators to pay for events.

• Utility allies slash chump blockers. If they give you some info about the top of the encounter deck, so much the better.

...That's it. Point her events at the enemy dome using your built-out economy, and occasionally deal with minions. If in doubt, Hex Bolt.

Superpower Training is in there as a de facto second copy of her tiara to make Hex Bolts worthwhile against high-difficulty enemies - you need to be able to bump 2-star cards up to three to hand out Stuns (or Toughnesses, whichever the enemy villain doesn't ignore).

The Sorcerer Supreme means you don't have much incentive to flip down unless you badly need to heal - try to cover yourself with a confusion from Professor X or Hex Bolt first if you must.

This is obviously a solo-centric build - three copies of One Way or Another scale poorly when you have to knock 12 threat off every side scheme, plus you'd rip through the encounter deck every couple of turns.

Competitively... I'm no Challenge-mode Ronan-killer. The deck can take down En Sabah Nur in Standard without breaking too much of a sweat even with my sub-optimal piloting, so I'm sure better players can handle tougher encounters.

Cards I don't own that would make the cut in an unlimited environment:

• Replace Helicarrier with Skilled Investigator.
• Replace Captain Britain with Dazzler.
• Replace Starfox with Ironheart.
• Replace Superpower Training with Under Surveillance if the main scheme threshold is <9P.
• I don't think replacing Multitasking with Clear the Area is worth it - you need the extra side-scheme thwarting power to mitigate OWoA.
• Turn the Tide (...which I do own, obviously, since it comes with Wanda!) suffers from Hex Bolt not being a Thwart action, so it's out.