May I ask some experienced users to perhaps create a list of common classical puzzles and common sudoku variants? LMI tests are often so variant-filled that I am somewhat confused what are the originals. Thanks in advance!
Adding to what Rajesh said, here is the link for Beginners Sudoku Contest, August 2013 - http://logicmastersindia.com/BeginnersSudoku/?test=B201308 On the right, there are links for the months before that. We've covered a good amount of common variants so far.