Canfield
Family: Klondike Family
A tough variant defined by a 13-card reserve and a random starting rank.
Canfield starts with a stacked "reserve" pile of 13 cards and 4 tableau columns, and the rank of the first card placed on a foundation becomes the starting rank for all the other foundations (for example, if you start on 7, every foundation runs 7→8→…→6).
Only the top card of the reserve is playable, so how you work through it decides the game. The stock can be cycled continuously in Draw 3.
Historically originating in casinos, it's famous for a low win rate, but it offers short, tense games.
Related variants
Klondike
The most widely known standard Solitaire. It's the default game on this site.
Open / Skill-basedYukon
A variant where you can move whole groups of cards even if they aren't in sequence.
Two-Deck (Double Deck)Forty Thieves
A hard, two-deck, 10-column classic where skill matters greatly.