Do a little experimenting and take the decks in your meta into account you can always add more or take some out as needed while playtesting and tuning your deck
The problem is no one is going to give you $0.25 for your Loch Dragon or Trail of Crumbs, so it is very important to only include commons and uncommons that have real value, rather than just including all of them at retail price
One of Magic's best demons, Bloodletter of Aclazotz does a lot for your life drain shenanigans in any format
Rogerthe Pirate Kingis the pinnacle of One Piece
Discarding lands to Gerrard's Verdict, however, will hand your opponent 6 life points, which is not a good result
more expensive cards will then lower the rate to 17.5% for cards up to 1,000 and 15% for the most pricey cards over a grand