SGamesSimon Tatham's PuzzlesDozens of logic puzzles in your browser, free and ad-free.chiark.greenend.org.ukOpen site
NGamesNonograms.orgThousands of puzzles where number clues reveal a hidden picture.nonograms.orgOpen site
CGamesConnectionsA daily puzzle of sorting 16 words into four groups by what they share.nytimes.comOpen site