Puzzles generated by gnome-sudoku
gs4 easygames: 100
gs4 mediumgames: 100
gs4 hardgames: 100
gs4 very_hardgames: 100
gs5 easygames: 100
gs5 mediumgames: 100
gs5 hardgames: 100
gs5 very_hardgames: 100
gs6 easygames: 100
gs6 mediumgames: 100
gs6 hardgames: 100
gs6 very_hardgames: 100
Puzzles from www.sudocue.net
The No-Trick Ponies Collectiongames: 250
The Learning Curve Collectiongames: 2500
The Superiors Collectiongames: 160
The Almost Daily Nightmare Collectiongames: 400
100 Snowflake Puzzlesgames: 100
Top 10000 Sudokusgames: 10000 :-)))) source