Discussion Forum

Lurking Predators is good although it still costs 4GG. There really isn't a secret card that just puts out bigger creatures (except Elvish Piper haha). Maybe try to put smaller creatures in your deck and then amp them up with enchantments later on. You can get mana acceleration cards like Llanowar Elves and Birds of Paradise. Green has a lot of really good mana accel cards like these: Fertile Ground, Cultivate, and Overgrowth.

the only card that comes to mind is Phyrexian Processor, although it cost you life it's a great card if you have slight advantage against your opponent, which should not be a point in a green/blue deck....

mass polymorph?
out of standard there is dramatic entrance and in standard there is summoning trap.

Cards that allow you to avoid paying a card's mana cost are usually very dangerous and can become broken if not designed well. As a consequence, you don't see a lot of them being printed. I think all the options in Standard have been mentioned by previous posters (except Master Transmuter, if you wish to drop artifact creatures).

Here's some older options:
Defense of the Heart
Pattern of Rebirth
Oath of Druids
Natural Order
Lure of Prey
Dream Halls
Show and Tell
Braids, Conjuerer Adept
Quicksilver Amulet
Belbe's Portal

Unfortunately, most of these cards can't be bought for cheap!

If you wanna run straight green you could try Khalni Hydras as they cost 1 less to cast for each green permanent you control which is fairly easy early game if you use a few visionaries, llanoawar and birds

other non standard options are

tooth and nail
Gamekeeper
Thicket Elemental
Brilliant Ultimatum
Intet, the Dreamer
Jhoira of the Ghitu

A good standard suggestion, especially for elves.
Would be : Genesis Wave.

wild pair will put out twice as many creatures as you would without it.