There isn't really a number, it's more of what you feel needs ratings.
Oh, I meant that some game jams have you need at least 20 rating to be in the ranking. But, nothing about it is said about it. So, I was confused. Also, I really can’t suggest any games as I haven’t played many as I am having my exam lately
After looking around I can't find anything either but good luck on your exam!
Thank you so much ❤️