Cryogen seems to be quite blog oriented, with Markdown conversion as one of the main features.
During the weekend I have made a quick test with Gatsby and CoffeeScript. Replacing CoffeeScript with ClojureScript would be quite nice, but I have not found anything similar to Gatsby in the Clojure world. Interestingly, Gatsby has plugins for CoffeeScript, PureScript, etc. (I understand CoffeeScript and ClojureScript are two completely different beasts).
I think it is time for me to take a closer look at the interoperability between React and Reagent. I think I have seen somewhere that Gatsby and ClojureScript do not play well together, but I did not understand the reasons yet.