Reddit mentions of Pickboy Mandolin pick, Nytro, 0.75mm, 10 picks

I use these for bluegrass picking. I thin out the bottom edge a bit with a fingernail file and smooth it down, and it's pretty well perfect for my otherwise crappy mandolin playing. This is an extra thick pick, and took a little trouble getting used to. But once you get the hang of it, a thinner pick just won't do.

Except for classical playing, where I prefer a little thinner and smaller pick, like these. Since I hold the pick a little different between bluegrass and classical playing, these work out great for the other pick grip for Calace-style.