I'm currently cobbling together a FlashCard Image Generator written in HTML/JS. So far it only generates a single image, not sure how it will perform on a larger scale, but if it works out, you'll be able to use your web browser to locally generate text-based flashcards from comma/tab-separated files (such as Anki exports). It's a low-priority project for me at the moment, so it may be vaporware for a while.
Anki actually has a similar addon already ( papercards
https://ankiweb.net/shared/info/2042118948 ) but it didn't work properly for me.
You can also find some printable PDF flashcards out in the wild, which could be used for this addon by converting the PDF flashcard to images, but it's hard to crop the correct regions for front / back.