I use these: https://www.amazon.com/dp/B01CHO5UHY/ref=twister_B07HSH738Z?_encoding=UTF8&th=1

"Nite Ize GlowStreak LED Dog Ball, Bounce-Activated Light Up Dog Ball", currently 8.99/ball on Amazon.

Why I like them:

• They are literally indestructible (because they are made for dogs lol). They are made out of silicone. You can throw them as hard as you want against a concrete wall and they will be fine.
• Bright LED lights that cycle through a variety of colors (with mellow transitions between colors). Just one setting.
• They are waterproof
• Good size/weight, weight is equally distributed
• Great price point

Only con:

• They are bouncy (which can be a pro), so if they touch each other mid-air, they bounce apart