If you take a careful look at the OP you'll see that Greiga Master has provided (mostly) clean rips from just about all the sprites we need. Some of them do have some problems, but I PMed him asking about the code he used, which I could maybe use to fix those (and extract anything else anybody needs).
By the way if anybody knows another/quicker way to contact him that'd be good too.
As MJ said though, most of the sprites on the site were ripped using traditional methods; I think only Mario Overworld, Bros Overworld and Corporal Paraplonk were done using Greiga Master's rips. So if anybody thinks that some of the existing sheets are incomplete feel free to fix those.
(This also reminds me that I should actually credit Greiga Master in my sheets, I'll do that now.)
EDIT: Noticed that Monty Mole and Yikk are also done with his rips (and fixed my submissions).
By the way if anybody knows another/quicker way to contact him that'd be good too.
As MJ said though, most of the sprites on the site were ripped using traditional methods; I think only Mario Overworld, Bros Overworld and Corporal Paraplonk were done using Greiga Master's rips. So if anybody thinks that some of the existing sheets are incomplete feel free to fix those.
(This also reminds me that I should actually credit Greiga Master in my sheets, I'll do that now.)
EDIT: Noticed that Monty Mole and Yikk are also done with his rips (and fixed my submissions).