Churchill Solitaire - The most diabolical version of solitaire ever devised. Played by Sir Winston himself. Available via the AppStore and Google.
PySolFC - PySolFC is a collection of more than 1000 solitaire card games. It is a fork of PySol Solitaire.
Microsoft Solitaire Collection - Play Klondike, Spider, Freecell, Pyramid, and TriPeaks! Plus, Daily Challenges!
World of Solitaire - Over 50 beautiful free web based Solitaire games. Klondike, Spider, FreeCell and more.
Treys - Like solitaire... but fun!
BVS Solitaire Collection - Award winning collection of solitaire card games for Windows/macOS and iPad/iPhone.