Where can I use these sprites? (Copyright)

[iyenal]

The sprites are usually used for animations and fan games. As long as they are free (this also means no in app purchases) the worst you can get is ceist and desist.

For downloading them and putting them up on another website, you really shouldn't. People work hard on sprite rips and customs and taking them on another site without their permission is just not nice.

Apart if you give the needed credits to the rippers.