How to understand which mollies are good which aren't?

I'm on the way to complete my tank's cycle. But I want to know that which mollies are good? I saw some ballon Molly I'm shops, but they ss slow to me.

All Molly are slow. Just pick the ones please your eyes. We all like eye candy lol.

On a side note, Molly are brackish fish. It means they naturally live in water with a little salt in it. They are livebearers, which means they will give birth to fish fry directly and you need some kind of population control or they will multiply too fast.