I think we're unlikely to get those ever again. Dark Pokémon, Delta Species, and a few other cards that incidentally played with Pokémon types had their day back when the Pokémon franchise was less of an established franchise with ex-Wall Street and Bloomberg-types holding central positions in the company (who then go on to hire people to write comprehensive series bibles that are more preoccupied with "Brand Integrity" than creativity) and could do more experimentation with these sorts of things, but even ignoring that, now that the series has found its legs, the old ideas brought back would be conceptually redundant to regional forms, one-off-per-generation gimmicks (e.g. Megas, Z-Moves, and so on). Pokémon prefers to keep things relatively simple and that kind of clash of ideas seems unlikely.
Having said all this, I'm still surprised that TPCI was able to get approval to print a Delta Species card of any kind of 2021 (Mimikyu δ), so I don't rule it out entirely.