What are the common deck strategies

other comments will tell you the hard-set-meta. But if you want the scoop on alternative meta notes here ya go.

Koffing Weezing Koga can be added to a myriad of decks that are slow to reach their energy as a safe hp sink that poisons.

Brock decks are worth a glance if you're missing good Exes for the big meta decks due to just starting out. Two Onixs and two brocks is really the fundamentals for it.

Original Mankey with reckless charge into primeape is a turn 3 100 damage.

Add butterfree if you have her full 6 card evolution set to any deck that has huge hp and doesn't need a lot of cards to work, basic Exes, for instance. She'll heal em.

If you find yourself struggling for good single energy opening cards (missing rapidash/blaine in your Charizard deck, for instance) use neutral-energied pokemon from other decks! Mienfoo and Mienshao are fighting types with high one energy damage (adv against normal and Pikachu, too!) And don't need fighting energy. Zubat-Golbat is another example.

Of course these all fall behind the perfect architecture decks once you have those. But these can be fun alternatives that are near-meta if you're missing cards!