Craftpix offers high-quality premium and free 2D-game assets for your project.
Game developer studio is a collection of thousands of 2D game assets all in one style. You can use the asset for both personal and commercial projects.
7. ITCH.io
Itch.io is a market place for indie games. You can buy games for all platforms on itch.io. It also has lots of game assets hosted on it for free.