Here a couple examples I came across recently of games which have multiple recent reviews, on the first page of reviews, that either outright state they received a counterfeit or describe quality control issues that almost certainly describe a counterfeit:

Catan https://smile.amazon.com/Catan-Studios-cantan2017/dp/B00U26V...

Splendor https://smile.amazon.com/Asmodee-SPL01-Splendor/dp/B00IZEUFI...

Ticket to Ride https://smile.amazon.com/Days-Wonder-DO7201-Ticket-Ride/dp/0...

Ticket to Ride: Europe https://smile.amazon.com/dp/B000809OAO/

7 Wonders https://smile.amazon.com/Asmodee-5511788-7-Wonders/dp/B0043K...

Azul https://smile.amazon.com/Plan-Games-Azul-Board-Game/dp/B077M...

They're not hard to find -- popular games from smaller publishers with high prices but relatively simple (cardboard/plastic) components seem to be what counterfeiters target.

I haven't had a problem either, but Asmodee did make a big stink about this last year: https://icv2.com/articles/news/view/39296/icv2-interview-asm...

What an interview. The whole time, there's this strong subtext that Amazon is the primary vector here, but they never come out and say it -- and dance around the issue of what corrective legislation would actually look like -- because they're evidently afraid of getting on its shit list, despite the massive harm its negligence is enabling.

Would you even know if they are good quality?

They can also be secondary runs, where the actual printer for the game does a second run after hours, with lower-quality components but original assets.