For many years my favorite and most successful call was my Quaker Boy Old Boss Hen diaphragm. Not so much anymore though..........I've bounced around and will just reach into my vest and pull one out and see how it sounds. If it is OK, that's the flavor of the day. If not I just dig in a little deeper.
One that keeps popping up is a Kits Call, I think. It is a yellow and I've been using it for a few years. Although Kits has been a defunct company for a number of years I had a few of their best stashed away.