Panharmonicon Holy sweet fun machine, Panharmonicon
Faithless Looting, Cathartic Reunion and Shriekhorn fill your graveyard with dredgers and payoff cards and dredge those cards once your yard is full
Now, while I am discussing the powerful range of answers that Kolaghan's Command has and the card advantage that ensues, don't forget Void either
Mana Dorks appear primarily in Green, as it is the Color that is best at generating mana
Relic of Progenitus has been one of the premium answers to some strategies: Its cheap, and can play a grindy game removing one card per turn, or one-shot-exiling both graveyards at the right time
Along with the classic Oblivion Stone, you have cards like Pernicious Deed and Sarulf, Realm Eater that can deal with multiple permanent types, but take a little while to get going, often over multiple turns