My favourite is the Match Winning Numbers filter - I believe I have it working successfully close to 100% of draws with an approx 55% reduction in lines for a 6 from 40 lotto. Being able to confidently 'reject' 2 million of 3.8 million lines is just wicked!
An example - for my 6/40 lotto it is VERY rare for any winning line to have less than 2 previously drawn set of 4 numbers or more than 7 of the same in the last 1960 draws. Now I just need some more filters like this - filters which rely less on the percentage of occurrence.