How long after do cards gain value

[Valonea]

So it's known that the card of a nation that stops existing begins to have more value generally, but when does that happen? How long after a nation stops existing should the card start gaining? I have three cards that's nations have disbanded but the flag doesn't say Ex-Nation yet

[Ivory Panther]

The flags will never say "Ex nation". That was a weird fluke of the first season, before they solidified things.

Without knowing the cards you're talking about, I'd guess your cards won't be worth much. Only if they're well-known and there will be a lot of folks who want their cards.

[Red And Alive]

oh ok cool thanks

[Noahs Second Country]

That's not exactly how it works. Odds are, if you don't have a high rarity or you aren't particularly influential, your card won't have any true value. You can always inflate a card, but having your nations CTE doesn't really make too much of a difference since there are thousands of CTE cards so far in S2.