A nice collection of maze puzzles, designed by Andrea Gilbert and Oskar van Deventer.
Here they combine logic puzzles with pictures. Think of Japanese puzzles and ingenious variations.
Cut-The-Knot is a website full of puzzles, mathematical surprises, and a bit of many other things. Not to be confused with cuttheknot.com, unless you're thinking about a divorce.
A puzzle platform based in Germany, in English, with a collection of old prize puzzles.
Erich's Puzzle Palace
Erich Friedman is an American mathematician with a passion for puzzles. He has a large collection of puzzle types that he invented himself, some
of which were used in official championships. Definitely a website worth visiting.
This is a Japanese website of which we don't understand a word, but if you follow the links in a clever way, you'll find some puzzles.
Angela and Otto Janko have a website in German with many logic puzzles that can be solved online. A very nice collection.
A website in German with optimization puzzles and also a puzzle wiki.
Logic Games Online
Josh Metzler implemented a few puzzles and single player logic games that can be played on his website.
Logic Masters India
Hosts regular puzzle competitions with puzzles created by our own Puzzlepicnic judge Bram de Laat and other puzzle authors.
If you like logic puzzles and recreational mathematics, then the website of Ed Pegg Jr. belongs in your bookmarks.
A Japanese publisher of puzzle books. The website has many puzzles, but to see them all you have to pay.