There are some funny things about roaring skies theme decks. One of them is Lightning Grass. Yup, Lightning Grass. When was the last time we had a Lightning Grass theme deck? ex Delta Species, which was around 9 years ago? Even funnier thing is that at least one theme deck in every set from Diamond and Pearl to Black and White sets had grass in it. That is 17 theme decks from that span, and none of those theme deck with grass in it had lightning in it.
After roaring skies, the next combination of 2 energy types from the original 6 energies, that is, not counting Darkness, Metal, or Fairy, to not have a theme deck for the longest time would be Lightning Psychic. The last time we had that was the Stormshaper deck from Platinum Arceus.
If counting Darkness, Metal, and Fairy, we don't have the following at all:
Darkness Fairy
Metal Fire, unless you count Steeplechase from ex Delta Species
Metal Psychic
Metal Fairy
Fairy Fire
Fairy Water
Fairy Lightning
Fairy Fighting