I am not a lawyer, I am certainly not your lawyer, and I have not examined the details of your specific case. This answer is meant to be educational, based on my understanding as someone who has worked under the OGL (but not as someone who has been responsible for ensuring the OGL compliance of our work). Especially if your motivation is primarily profit, you may wish to speak with a lawyer before pursuing this, as otherwise you will be assuming the risks associated with your actions (e.g. in the event that I am wrong about anything).
That out of the way, here’s my understanding:
You can copy the full text of Open Game Content, verbatim, freely or for profit. This much I am pretty confident in—there are a lot of copies of Open Game Content out there that are not associated with the original copyright holder. E.g. d20pfsrd.com hosts Open Game Content from Pathfinder by Paizo, but is unaffiliated with Paizo. There has even, at times, been some tensions between the two, but Paizo hasn’t claimed that d20pfsrd.com is not allowed to host the Open Game Content that it does. And Pathfinder 1e itself is based on Open Game Content from Wizards of the Coast, and despite Pathfinder being the primary competition for D&D, Wizards hasn’t sued Paizo over selling Pathfinder. So copying the full, verbatim text of Open Game Content should be no problem, nor should selling it.
However, I believe you are limited in that any “derivative work” you create from Open Game Content will also be Open Game Content. That means anyone can take what you make and upload it on a website for free, even if you would prefer people buy it from you, potentially limiting your sales.
(Realistically, with piracy being as prevalent as it is, anyone choosing to pay you for your work is basically volunteering to do so regardless. Even if your work is entirely original and cannot be copied or distributed legally by anyone, it still will be. So it might not make that much difference.)
The exceptions here are Product Identity, which can cover a fair few things—characters, spells, items, and similar elements can be declared Product Identity and then would have to be left out of any legal copy of your work. Artwork and other graphical elements are likewise usually Product Identity, so people couldn’t legally just put your entire PDF up online, even if all of the text is Open Game Content.
Luckily for you, Product Identity can include “trade dress,” which I believe would include the design of your cards. Therefore it’s unlikely that anyone could directly copy your work here—and may mean your product will have value in the marketplace.
