Just a heads up the "10,000 in 1" game claims that every of these devices advertises isn't something you should consider. It's going to be a lot of games you've never heard of for older systems like the NES so they fit on lower capacity SD cards. Potentially in multiple languages. It also comes on SD cards most people would recommend replacing.
It's better to just download the entire library, individual games, or an already curated collection.