What is your favorite kind of fidget toy/stim toy?

I honestly do not know the difference between and a stim toy and I usually use the two terms interchangeably.

My favorite fidget toys is my flippy chain. I use this thing all the time and take it with me everywhere. And I love that it's discreet and quiet.

What's your favorite fidget toy, or thing yiu like to fidget/stim with?