Any print of a card that's functionally identical to a card that's in-format is legal. (Not counting foreign or World Championship cards of course.) Energy are no different to Pokemon or Trainers in this regard. Just keep in mind that (usually, there's a small number of exceptions that have official errata and are allowed regardless, like Rare Candy or Potion) any functional difference disallows them being used. For instance, you can't use a Rocket set Rainbow Energy since it inflicts damage instead of placing a damage counter, but you could use one from, say, Platinum or XY.