John Rausch: Archive of puzzles
Mr Puzzle
Brian & Sue Young trading as Mr Puzzle since 1993 & on the web since 1998
Puzzles.com is a premier puzzle website about puzzles and optical illusions, magic and origami, scientific toys and math diversions, other things that involve intellectual recreations.
TW. Puzzles Homepage
Trevor Wood is craftman and puzzle designer. He is making excellent wooden puzzles.
Mathpuzzle.com
Ed Pegg Jr: Many puzzle-problems and links.