When I was little, my favorite "stimmy" toys were ... well, I don't know the official name of either one. But I loved the "mooing" cans/boxes that, when tipped over, slowly shifts something inside of them and makes a long squeak/"moo"/sheep sound. They felt awesome and I liked the sound. I also liked the wooden puppet animals that "collapse" when you push on a button underneath their stand. Also stress balls with jelly inside, really any things to squeeze.
I still like stress balls like that, but also the fidget cube is pretty nice.