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If there was a port, the most realistic addition would be from Gen 8 via SwSh BDSP and Legends, or maybe Gen 9. Your choices would be Cinderace, Toxtricity, Garchomp, or any of the pokemon made relevant in Legends.
If there was a new game coming that soon, the most realistic addition would be the cat and maybe a Gen 5 rep via remake buzz, likely Zoroark.
If there was a new game, say 5 years later, the next rep would be from Gen 5 remakes or Gen 10. Again, Zoroark gets a chance.
and to scare smash autists:
If Goh's Cinderace is staying in the anime, Cinderace will be added at any possibility thanks to being a hot topic pokemon in promotional media.
Low chance though, but let that sink in.