At the moment the only standard legal card that allows you to search for any card is Diabolic Tutor that was just reprinted in M14.
Although since you mentioned Greenseeker I guess you don't play standard.
Garruk, Primal Hunter is by far my favorite card for green card draw. His -3 ability allows you to draw cards equal to the power of the highest powered creature you control. And the best part, since he starts off with 3 loyalty counters on him you can knock off his ability as soon as you play it. Sure it'll kill him instantly, but depending on how many cards you draw it is WELL worth it.
Also the M14 Garruk (Garruk, Caller of Beasts) that just came out is handy for thinning out the deck. His +1 is a built in Lead the Stampede (also a good deck thinner. Lets you look at top 5 cards in your library, reveal any creature cards, and put the rest on the bottom of your library). His -3 lets you place any green creature in your hand onto the battlefield (hehehe....hello Progenitus....), and his -7 ability puts an emblem on the field that states whenever you cast a creature spell, you may search your library for a creature card and play it on the field as well.
Hunter's Insight is a pretty decent card. Its an instant that allows you to choose a creature you control and whenever it deals combat damage to a player or planeswalker, you draw that many cards.
There's also the Garruk's Horde which allows you to play with the top card of your library revealed and you can cast creatures from the top of your deck.
And Into the Wilds is a fun card to combo with that. At the beginning of your upkeep you reveal the top card of your library, if its a land card you put it in play.
So with both of those cards on the field, you start playing creatures from your deck till you get a land. Next turn you can play that land from your deck, draw another card from your deck, then hopefully the next card in your deck it another creature that you can play.
And then of course my all time 2nd favorite card in MTG history (with Birds of Paradise being the 1st....ALL HAIL THE RAINBOW MANA CHICKEN!!!), Green Sun's Zenith. For just 1 more green mana you can play ANY green creature in your deck. And then you can shuffle Green Sun's back in your deck. Nothing like running a playset of those babies with green draw power and you just keep on getting em. XD
Other than those there are the obvious cards like Harmonize (draw three cards), Sylvan Library (essentially draw 3, pick 2 and put them back unless you play 4 life per card), Garruk's Packleader (whenever a creature with power 4 or greater enters the battlefield, draw a card) and Momentous Falls (sac a creature, draw cards equal to its power and gain life equal to its toughness; awesome card to combo with Hunter's Insight after it's done the damage).
Hope this helps!! :)