Essentially, any psychic pokemon with a 3 energy attack cost can attack for just one psychic (assuming there is at least one colorless in the attack cost). Somethings that will be able to attack for one energy.
Mewtwo EX (Psy Drive can be viable, doing 120)
Sigilyph with Safeguard
Trevenant
Cofagrigus PLF (70 and disrupts coin flips for a turn)
Chandelure EX (70 plus burn and confusion).
Gallade (Potential Pyroar Counter)
I'm sure there are some I'm missing, but I think being able to do all these attacks for one energy (especially combined with some powerful abilities) could make for a potent strategy.
Mewtwo EX (Psy Drive can be viable, doing 120)
Sigilyph with Safeguard
Trevenant
Cofagrigus PLF (70 and disrupts coin flips for a turn)
Chandelure EX (70 plus burn and confusion).
Gallade (Potential Pyroar Counter)
I'm sure there are some I'm missing, but I think being able to do all these attacks for one energy (especially combined with some powerful abilities) could make for a potent strategy.