There are a couple variations that can be made with the free blue/green deck. The deck can be highly creature oriented or creature control heavy.
Cards that specialize in a theme (rouges and wolves) should be culled out, since the deck would be hard pressed to carry any specific creature theme. Taking out Nimble Dagger and Llanowar Charm right away.
Keeping the efficient creatures, creature enchantments, and spells, the deck starts to take shape:
Sentry Rogue X2
Aura Finesse x1
Time Ebb x3
Llanowar Elf x3
Lone Wolf x2
Giant Growth x3
This selection gives 40 cards to try the deck.
Some of the less efficient creatures (Obsidian Golem and Sentry Rogue) can be switched out for more creature control cards (Entangling Vines, Plummet and/or Surgical Precision) or better cards from the free booster.
Of course, this is just one deck idea and the deck can either be a green deck with a few blue cards thrown in or vice-verse.
Complete blue/green list