Well it depends what you call good. I actually went to a prerealease and pulled nothing usable but I was able to spread. I think that the following are good as they give you an actual theme for your deck.
1. Cacturne-spread and more spread 2 energy and 50 damage is good and Unown G can not stop it.Yay!
2.Manectric-hurts popular G pokemon and stops spreading.
3.Crobat G-not powerful but gets Cacturne started.
4.Bronzong G- spreads damage and deals decent damage to the defending pokemon. Also allows you to reorganize energy.
5.Zangoose- Invite and Strike is the ideal starter for this deck as it can spread damage very quickly while keeping your opponett off balance.
This deck went 4-1 with its only lost against a kid who had 2 giratina,2 diagla, and 2 palkia. This deck is somewhat quick ,but the flaw is lack of a big hitter. I think the spreading deck could have beat most as a lot just put together their best cards and hope for luck.
Alas I think the best single card is Manectric because alot of people at PT PR had a lot of powers in their decks.