Four columns play by Canfield rules, five play by Forty Thieves rules, and you can shift runs between them if both sides allow it. A 96% win rate.

The tableau here is split into two halves that play by different rules. The four columns on the left follow Canfield Solitaire, and the five columns on the right follow Forty Thieves Solitaire. You can shift sequences from one side to the other as long as the move is legal on the side you're taking cards from and the receiving side's rules accept the top card.
Thomas Warfield created this one. It's an easy game with a 96% chance of winning, played with two decks, where skill matters more than luck.
Related games include Demonthief, Demons Rush, Triple Demons, Quadruple Demons, and Yukon Puzzle. If you'd rather play it straight, original Solitaire is always an option.
If you run into anything odd or have an idea that would make the game better, please contact me.
Enjoy yourself!
8 foundation piles: Build in suit from whatever rank is dealt to the first pile, wrapping from King to Ace as needed, until each pile holds all 13 cards of its suit.
9 tableau piles: The first four piles build down by alternating color. The remaining five always build down in the same suit, with no wraparound, so a run stops at the Ace. A group of cards may move together if it's a valid descending run for that pile. Any card, or a valid run of cards, can fill an empty spot. At the start, one card is dealt to each of the four piles on the left, and eight cards to each of the five piles on the right.
Stock: Click to turn over 1 card at a time to the waste. You get two redeals, three passes through the stock in all.
Waste: The top card can be played on the foundations or tableau.
Reserve: The top card can be played on the foundations or tableau. 13 cards are dealt here at the start of the game.
There are eight foundation piles.
Each foundation pile gets a random starting card, and the rest of that pile builds up from there.
A card can be added to a foundation pile only if it's one rank higher and the same suit as the pile's current top card, so the only card that fits on a 7 of clubs is the 8 of clubs. A pile can hold no more than 13 cards.
The top card of each foundation pile can be moved back into play if another pile will accept it.
There's one reserve pile, dealt 13 cards at the start. The top card is face up; the rest are face down. No cards can be moved into the reserve, but its top card can be played to the left tableau, the right tableau, or the foundation.
There's one waste pile; the rest of the cards make up the stock.
Clicking the stock deals one card to the waste. You get two redeals, three passes through the stock altogether, before it runs dry for good.
The top card of the waste can be played to the left tableau, right tableau, or foundation.