For some cards like Gardevoir LV X, it's of course impossible. But for a card called Call Energy, it's quite easy of a guess. First of all, it's an energy. Second of all, it calls something, hence the name. It won't call a Benched Poke (since we have Warp/Cyclone for that) so it will probably call something from the deck. So I think it's a mini-Call for Family. Or maybe from the discard pile, but then it would be more like Resurrection Energy. And kinda broken (it would make Garchomp LV X obsolete).