I've used almost all of them. Slates, mouth, box, push peg. It's hard to use a box or slate when a bird is up close. Even behind a blind concealing motion I still have use both hands. Up close, I'll use a mouth or push peg. Push peg is another undedrated call I think a lot of hunters never try.

[Linked Image from i.imgur.com]
https://vcdl.org/