After the newest patch it's impossible to get achievements and gwent cards aren't dropping anymore. I know this is probably because i use debug console, but i've never cheated, i use it only for screenshot taking and i'm punished because of that? Now i'm FORCED to use cheats and all the gwent cards collecting has gone to shit. Really is it so hard to give us freedom? That's what PC is all about. Like that is not enough the newest patch disabled the console.
I thought CDPR are better than that. I pay for the game and can't enjoy it fully because developers decide how i play it. I chose PC because over console because of freedom it gives.

Gwent cards only drop from a limited pool, not *all* of them can be won from randoms.

Some you have to purchase, and some are quest rewards.

You may have 'run out' the pool.

If you don't mind spoilers you can check which cards you have/need here:

http://gwentcards.com/

After beating someone it says what card did you receive and it's not in my deck, double checked it. I missed 20-30 cards already. None of the major characters gave me a card, like Crach, Ermion and others.
Besides that even if i could get cards i wouldn't get the achievement for it because CDPR has disabled them.

Cards:
They are split into *four* decks *plus neutrals, which are available to all four simultaneously*.

In addition to the unit and hero cards, plus weather and muster/scorch, which appear in *either* the left hand pool, or right hand "deck" depending on whether they are equipped for that faction or not, there are four "leader" cards, which you need to view using the "change leader" action (x on PC)

You won't see new monsters if viewing the Nilfgaardian deck, and new Nilfgaardian cards won't appear in your hand in play if you don't add them to the active play-deck.

It is in your interest to not overpopulate the play-deck, keep it to 22-24 cards, with limited heros and modifier cards, using the strongest cards, medics and spies which can be reused, while heroes are one-shot but invulnerable. Decoys and medics, with spies can stretch your deck considerably.

Unsure about achievements as I don't run with Galaxy at all, but I was notified that I had completed "Collect them all" yesterday, so the testing necessary for achievements is working as it should.