The current format is BCR-on, meaning cards from the sets Boundaries Crossed, Plasma Storm, Plasma Freeze, Plasma Blast, Legendary Treasures, XY, Flashfire, Furious Fists and Phantom Forces can be used in tournaments.
Or you could simply look for these symbols at the bottom-right part of the card (the sets were named in the order of release, just like the symbols):
BCR
PLS
PLF
PLB
LTR
XY (duh)
FLF
FFI
PHF
Keep in mind, however, that TPCi rotates out 3-4 sets every year, which means cards from those sets won't be legal anymore. This season however, the Expanded format was introduced, and the format here is BW-on. This means that you can use any card from the sets Black & White, Emerging Powers, Noble Victories, Next Destinies, Dark Explorers and Dragons Exalted, in addition to the above sets. Here are the symbols and abbreviations:
BLW (yes, for some reason this one isn't BW)
EPO
NVI
NXD
DEX
DRX
The Expanded format however isn't really used that much in big tournaments, so preparing for Standard/Modifed (BCR-on) is the best. However, you must prepare for both if you are aiming high.
PS: Primal Clash (no abbreviation or symbol as of now) is getting released later this year, and that set will be legal as well.
PS2: Since the release of FFI, TPCi made a rule stating that any released set will become tournament legal only 23-ish days after the official release.
PS3: Sometimes TPCi "reprints" a card. I'll take Pokémon Catcher as an example. It was first released in EPO, which was rotated out, meaning the card was no longer legal in tournaments. However, a card with that same name with no major changes in the effect was released in PLB, so you would be able to use your old Catcher in a tournament as long as PLB remains legal.
Basically here's the rule (applies only for Midifed and Expanded formats): You may use any card from any set, as long as a card with the same name with no major changes exists in a tournament-legal set.
PS4: There's a 3rd format called Unlimited, it however is not used in tournaments and you only use it with friends.
So i have a few cards that I'd like to know are legal or not, they're from base set and bs2...
Energy search (search your deck for basic energy card, show it to your opponent and put into hand.)
Recycle (flip a coin. If heads, put a card in your discard pile on top of your deck.)
Potion (remove two damage counters from 1 of your Pokemon) asked this because wording is different
Energy removal (choose one energy card attached to one of your opponents Pokemon and discard)
Bill (draw 2 cards)
Super potion (discard one energy attached to one of your own pokemon in order to remove up to 4 damage counters from that Pokemon)
Sabrina's gaze (each player shuffles hand into deck and draws new hand of same number of cards)
Energy amplifier (choose an energy card in your hand, show it to your opponent and shuffle it into your deck. Then flip a coin. If heads, search your deck for up to
3 basic energy cards. Show them and put them into your hand)
Gambler (shuffle hand into your deck. Flip a coin. If heads draw 8 cards, tails draw 1)
Mail from Bill (you can't play this card if you have five or more cards in your hand. Draw cards until you have exactly 4 cards in your hand.)
With most its just wording (like I don't think Sabrina's gaze is legal, but doesn't hurt asking) and do I need the newer version in order to play it? Or just be able to prove that it has a reprint?
TIA