Any free games for two passing one device to each other?

This is usually called hotseat mode, that may help with searching. Polytopia and unciv both support this and are great turn based games.

Risk is free but you only get one game per day. It's only around $5 if you want to purchase unlimited games, and I found that to be more than fair

I play chess with my kids this way.

AppleFlinger is somewhat like Angry Birds...