I'm wanting to get into competitive play so what decks should I play in expanded and standard. Shaymin is probably not a problem, but try not to give me decks that run 4 unless they are absolutely awesome.
Hi dkatz! Glad to see you're interested in competitive play.
If you're looking for a full list of popular decks in both formats, the
Metagame Deck Discussion forum has threads for all the top decks in each format, each including skeleton deck lists and discussions. Of those decks I can suggest a few in particular to start out with.
In Standard I would recommend either Vespiquen or M Manectric-EX. Both decks are high tier competitors that aren't particularly difficult to play, and both aren't particularly expensive; they only use 2-3 Shaymin-EX.
Vespiquen is a very fun, consistent, cheap deck that will probably stay competitive for a little while. It uses cards like Battle Compressor, Ultra Ball, and Professor Sycamore to discard a bunch of Pokemon, then do high damage with Bee Revenge. However, there are a few complicated concepts you'll need to understand about the deck to play it effectively.
M Manectric-EX is much simpler to play and is quite powerful in the current metagame. You simply attach Energy to Manectrics and use Turbo Bolt to power up varied attackers, or other Manectric. It can be played alongside an array of alternate attackers. It is more expensive to build though.
In Expanded Vespiquen/Flareon (same idea as Vespiquen) is very strong, but is similarly difficult to play. Another deck worth considering in Expanded is Yveltal-EX. It uses several Basic Darkness Pokemon like Yveltal-EX, Yveltal, and Darkrai-EX along with Dark Patch to power them up for quick, high damage attacks. Other cards like Hypnotoxic Laser and Seismitoad-EX give the deck a lot of options in many situations. The deck is fairly easy to understand, although a bit difficult to play at top level tournament play.
You can find more info on these decks in the Metagame Deck Discussion forum.
I hope this post was helpful! Feel free to ask me any more questions.