I cover your feet and keep them warm. I always come in pairs, but sometimes I'm left all alone. What am I?

I show feelings without words and am often sent on a phone. What am I? Solve the riddle → I open wide for your yummy snacks. You carry me with you and then bring me back. I keep your food safe and sound. What am I? Solve the riddle → I'm round and float high, full of air but completely empty inside. One poke and I'm gone with a sigh. Solve the riddle → I make a 'ding' or a 'clang' sound. I have a clapper inside, but no mouth to speak. What am I? Solve the riddle → You throw a ball through me to score points. What am I? Solve the riddle →