A relatively recent imprint, the American Mystery Classics range was launched in late 2018 by Penzler Publishers.
The range reprints classic works of American mystery fiction in paperback and hardcover, each presented with a short introduction. The range has presented mystery fiction in a variety of styles ranging from impossible crimes to sensation fiction and legal mysteries.
Being still quite a new range I have only dipped into a few titles although I have quite a few on my TBR pile. As such I have no particular recommendations but I will note that I did nominate The So Blue Marble as a candidate for Reprint of the Year in 2018.
A Note: I reviewed The Dutch Shoe Mystery prior to the title being republished in this range but I include it below as the mystery itself is obviously the same.