On Sword Shield and Scarlet Violet cards, what do the "F" and "G" indicate?

LeDabMaster

I started getting into the PTCG early last month, and one that's been baffling me is the letter on the bottom left corner of the cards that sit next to the expansion symbols and expansion codes. The "F" in Sword Shield cards and the "G" in Scarlet Violet cards. Do those letters indicate a card is part of a series of expansions based on the core video games?

Octowen

You’re close. They are the “regulation mark” on the card. They help make things simpler when rotation happens. For instance, last rotation, the “D” regulation mark rotated. So now E, F, and G regulation marks are legal. It is likely that come January or February, the E regulation mark will rotate, and the new expansions will have the H regulation mark.