I made an article listing 10 reasons why indie games use pixel art.
In it, I've included links to some free pixel art games, free sprites, free backgrounds and free tile sets.
Edit (Updated link): https://www.pixliz.com/post/why-indie-games-pixel-art
Edit (Following is Expired):https://pixliz.com/pixliz-blog/f/why-do-indie-games-use-pixel-art
Let me know if you found this helpful!