Dorado

I'm looking at possibly getting a derringer for side matches and just for fun. I don't know anything about them other than they are small and only good at card table ranges. So I'm looking for suggestions on what to get. I'd like something like a .357/.38 or in .45 as I have reloading dies for those. I currently shoot .38s but I'd have little to no trouble working up a load for a .45. I'd like to stick to one of those calibers instead of a .25 or .32. What would y'all suggest? What should I look for?