HGSS ERA cards(HGSS-CoL) along with a new format.
This would allow for many very popular (and fun) decks to be made. A new format, similar to the legacy format of the official game, with hgss-bw legendary treasures, would probably be extremely popular as it is in the official game.
Anonymous shared this idea
started · Adminaxpendix (Creator, TCG ONE) responded
We’ve released the first two expansions HGSS and UL together with HGSS-on format. We are working on the rest.
i want pokemon heart gold and soul sliver card