Yes, there is an app named "Stamurai" and most of the participants are from South Asia (India, Nepal, Pakistan...) .There you can have impromptu speaking with fellow stutterers. I am also using it and it has been helping me a lot since I am also a non-native English speaker. Plus, you could have 2 to 3 calls per day. Tho the impromptu speaking meetings are free of cost, you have to take a subscription for other content.