Paul Stamets is probably most famous one. I also heard Michael Pollan on Tim Ferriss podcast mention that he know Stamets and one other guy (didn't want to tell his name) who cure stutter with mushrooms and that it's common for mushrooms to fix stuttering... even tho I didn't hear any more stories about mushrooms/psychedelics permanently curing/improving stutter. There's also this https://www.psymposia.com/magazine/psychedelics-and-the-full-fluency-phenomenon/ Personally I only tried smaller dose of mushrooms and it has no effect I think, but planing to have a bigger dose. Hope that now when psychedelics are getting more attention in scientific community we will see some kind of solutions to help fix stuttering.