Is a Pokémon energy card with no numbers normal?
In Japan, most Basic Energies ever printed don't have any set number, because they were unnumbered. This is in contrast to English cards, where all Basic Energies were numbered up to Call of Legends expansion. Since Black &amp; White expansion, most Basic Energy cards are also unnumbered, with the exception of cards found in booster packs as they have a different illustration.

Bulbapedia has nice collection of Fire Energy cards, including some Japanese cards without set number (click to enlarge):