Below is an excerpt from fatherly.com
There are a few ways to witness pure toddler joy in action: You can put your kid in an outdoor swing and let them soar through the air and kick their pudgy little legs around. You can let them, oh, say, play with butter, or thanks to the latest brilliant trend in sensory play, you can also let them roll around in a baby ball pit full of… well, plastic balls. In a world crowded with STEM toys and others that make big claims about development, the best baby ball pits are a refreshingly simple way for kids to experience what play really means: letting go and having fun. But before you invest in a ball pit for kids, there are a few things you must keep in mind: Make sure your child can sit up on her own before using it. Unless you have tons of floor space, you’ll want a ball pit that folds up and keeps the balls contained. And you want balls you can clean. The reason for that shouldn’t need any further explanation.
A ball pit that actually won't give aesthetic pain? Here it is. It comes with 300 balls, and is made from a soy-based foam with an organic cotton outer layer. The balls are crush-proof, and the pit itself actually looks, dare we say it, elegant.