Recycling can be a wonderful thing, whether it be recycling plastic to help the environment, or onto something like recycling parts of an older essay to submit as a newer one for class (That is plagiarism by the way, you probably shouldn't do that). The Pokemon Company seems to like the idea of recycling ideas, and seems to be doing so for the third time now! After spending about six years or so in the vault, Pokemon "ex" seem to be making a return to the scene in generation 9.
Above is an image of the two legendary bikes in Scarlet and Violet, which are the first two Pokemon to have their "ex" cards shown to us. What we know about these cards is extremely limited, as we only have this and one other image (below) to go off of, what we do know however is enough to start forming some cohesive thoughts. To begin with, the Pokemon seem to have to evolve into these new cards, which will certainly spice up the way that they're played. This was something we saw with the first "ex" reboot which started in the Unova era. This is a big difference then the second generation of "EX" cards, which started during the Unova era, and did not need to evolve from anything to be put into play.
Since much of the cards that have been revealed to us are missing many important features, it is safe to assume something is being hidden from us. Perhaps the brand new Terastal Phenomenon will play a part into these new cards.
In order for some reference, a card of the first and second "ex" and "EX" lines will be shown below. On the left is a Dragonite card from The Ruby and Sapphire era, and on the right is a Dragonite from X and Y.
We don't have much news to go off of right now, so hardly much can be said without diving into speculation. If you have any insight, thoughts, or questions feel free to write away in the comment section down below. Whenever more news comes out, make sure to check out the Stadium for a quick summary and analysis.